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Zimberg IZ, Ftouni S, Magee M, Ferguson SA, Lockley SW, Rajaratnam SMW, Sletten TL. Circadian adaptation to night shift work is associated with higher REM sleep duration. Sleep Health 2024; 10:S112-S120. [PMID: 37914630 DOI: 10.1016/j.sleh.2023.08.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 08/31/2023] [Accepted: 08/31/2023] [Indexed: 11/03/2023]
Abstract
OBJECTIVE To investigate the influence of the degree of circadian adaptation to night work on sleep architecture following night shift. METHODS Thirty four night workers (11 females; 33.8 ± 10.1years) completed a simulated night shift following 2-7 typical night shifts. Participants completed a laboratory-based simulated night shift (21:00-07:00 hours), followed by a recovery sleep opportunity (∼09:00-17:00 hours), recorded using polysomnography. Urinary 6-sulphatoxymelatonin (aMT6s) rhythm acrophase was used as a marker of circadian phase. Sleep duration and architecture were compared between individuals with aMT6s acrophase before (unadapted group, n = 22) or after (partially adapted group, n = 12) bedtime. RESULTS Bedtime occurred on average 2.16 hours before aMT6s acrophase in the partially adapted group and 3.91 hours after acrophase in the unadapted group. The partially adapted group had more sleep during the week before the simulated night than the unadapted group (6.47 ± 1.02 vs. 5.26 ± 1.48 hours, p = .02). After the simulated night shift, both groups had similar total sleep time (partially adapted: 6.68 ± 0.80 hours, unadapted: 6.63 ± 0.88 hours, p > .05). The partially adapted group had longer total rapid eye movement sleep duration than the unadapted group (106.79 ± 32.05 minutes vs. 77.90 ± 28.86 minutes, p = .01). After 5-hours, rapid eye movement sleep accumulation was higher in the partially adapted compared to the unadapted group (p = .02). Sleep latency and other stages were not affected by circadian adaptation. DISCUSSION Partial circadian adaptation to night shift was associated with longer rapid eye movement sleep duration during daytime sleep, highlighting the influence of entrainment between the sleep-wake cycle and the circadian pacemaker in night workers. The findings have important implications for sleep and subsequent alertness associated with shift work.
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Affiliation(s)
- Iona Z Zimberg
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Suzanne Ftouni
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Michelle Magee
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Sally A Ferguson
- Central Queensland University, Appleton Institute, Goodwood, South Australia, Australia
| | - Steven W Lockley
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Shantha M W Rajaratnam
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia; Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Tracey L Sletten
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.
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Sletten TL. Melanopic metrics: Advancing the characterization of everyday light patterns. Proc Natl Acad Sci U S A 2023; 120:e2316004120. [PMID: 37991937 DOI: 10.1073/pnas.2316004120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2023] Open
Affiliation(s)
- Tracey L Sletten
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Melbourne, VIC 3800, Australia
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Sletten TL, Weaver MD, Foster RG, Gozal D, Klerman EB, Rajaratnam SMW, Roenneberg T, Takahashi JS, Turek FW, Vitiello MV, Young MW, Czeisler CA. The importance of sleep regularity: a consensus statement of the National Sleep Foundation sleep timing and variability panel. Sleep Health 2023; 9:801-820. [PMID: 37684151 DOI: 10.1016/j.sleh.2023.07.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 09/10/2023]
Abstract
OBJECTIVE To develop and present consensus findings of the National Sleep Foundation sleep timing and variability panel regarding the impact of sleep timing variability on health and performance. METHODS The National Sleep Foundation assembled a panel of sleep and circadian experts to evaluate the scientific evidence and conduct a formal consensus and voting procedure. A systematic literature review was conducted using the NIH National Library of Medicine PubMed database, and panelists voted on the appropriateness of 3 questions using a modified Delphi RAND/UCLA Appropriateness Method with 2 rounds of voting. RESULTS The literature search and panel review identified 63 full text publications to inform consensus voting. Panelists achieved consensus on each question: (1) is daily regularity in sleep timing important for (a) health or (b) performance? and (2) when sleep is of insufficient duration during the week (or work days), is catch-up sleep on weekends (or non-work days) important for health? Based on the evidence currently available, panelists agreed to an affirmative response to all 3 questions. CONCLUSIONS Consistency of sleep onset and offset timing is important for health, safety, and performance. Nonetheless, when insufficient sleep is obtained during the week/work days, weekend/non-work day catch-up sleep may be beneficial.
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Affiliation(s)
- Tracey L Sletten
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Matthew D Weaver
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Russell G Foster
- Sleep & Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - David Gozal
- Joan C. Edwards School of Medicine, Marshall University, Huntington, West Virginia, USA
| | - Elizabeth B Klerman
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA; Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Shantha M W Rajaratnam
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Victoria, Australia; Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Till Roenneberg
- Institutes for Occupational, Social, and Environmental Medicine and Medical Psychology, LMU Munich, Munich, Germany
| | - Joseph S Takahashi
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, Texas, USA; Howard Hughes Medical Institute, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Fred W Turek
- Center for Sleep and Circadian Biology, Department of Neurobiology, Northwestern University, Evanston, Illinois, USA
| | - Michael V Vitiello
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, USA
| | - Michael W Young
- Laboratory of Genetics, The Rockefeller University, New York City, New York, USA
| | - Charles A Czeisler
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA.
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4
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Crowther ME, Saunders WJ, Sletten TL, Drummond SPA, Bei B. Tailoring cognitive behavioural therapy for insomnia across contexts, conditions, and individuals: What do we know, where do we go? J Sleep Res 2023; 32:e14023. [PMID: 37641983 DOI: 10.1111/jsr.14023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 08/03/2023] [Indexed: 08/31/2023]
Abstract
Cognitive behavioural therapy for insomnia (CBT-I) is considered the front-line treatment for insomnia. Despite the demonstrated effectiveness of CBT-I, it is necessary to consider how CBT-I may be tailored to different individuals. The purpose of the present review is to provide a summary of literature on tailoring CBT-I to different individuals and provide directions for future research. This review focused on the following domains of adaptation: (i) tailoring CBT-I components to individuals with comorbid mental or physical health conditions such as comorbid depression and pain; (ii) adapting CBT-I delivery for different contexts in which individuals exist, such as inpatient, educational, and different social/cultural settings, (iii) adapting CBT-I to specific individuals via case-formulation in clinical settings. We highlight current gaps in the exploration of tailored CBT-I, including a lack of research methodology to evaluate tailored interventions, a need for the integration of ongoing individualised assessment to inform treatment, and the necessary involvement of consumers and stakeholders throughout the research and treatment development process. Together, this review showed abundant adaptations in CBT-I already exist in the literature. Future research is needed in understanding when and how to apply adaptations in CBT-I and evaluate the benefits of these adaptations.
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Affiliation(s)
- Meagan E Crowther
- School of Psychological Sciences, Faculty of Medicine, Nursing and Health Sciences, Turner Institute for Brain and Mental Health, Monash University, Melbourne, Victoria, Australia
| | - William J Saunders
- School of Psychological Sciences, Faculty of Medicine, Nursing and Health Sciences, Turner Institute for Brain and Mental Health, Monash University, Melbourne, Victoria, Australia
| | - Tracey L Sletten
- School of Psychological Sciences, Faculty of Medicine, Nursing and Health Sciences, Turner Institute for Brain and Mental Health, Monash University, Melbourne, Victoria, Australia
| | - Sean P A Drummond
- School of Psychological Sciences, Faculty of Medicine, Nursing and Health Sciences, Turner Institute for Brain and Mental Health, Monash University, Melbourne, Victoria, Australia
| | - Bei Bei
- School of Psychological Sciences, Faculty of Medicine, Nursing and Health Sciences, Turner Institute for Brain and Mental Health, Monash University, Melbourne, Victoria, Australia
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Reynolds AC, Kyle SD, Sletten TL, Adams RJ. Cognitive behavioural therapy for insomnia: Can we make it work for shift work? Sleep Med Rev 2023; 72:101864. [PMID: 37864915 DOI: 10.1016/j.smrv.2023.101864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 10/05/2023] [Indexed: 10/23/2023]
Affiliation(s)
- Amy C Reynolds
- Flinders Health and Medical Research Institute (Sleep Health)/Adelaide Institute for Sleep Health, Flinders University, Bedford Park, SA, Australia.
| | - Simon D Kyle
- Sir Jules Thorn Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, UK
| | - Tracey L Sletten
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton VIC, Australia
| | - Robert J Adams
- Flinders Health and Medical Research Institute (Sleep Health)/Adelaide Institute for Sleep Health, Flinders University, Bedford Park SA, Australia
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6
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Varma P, Postnova S, Phillips AJK, Knock S, Howard ME, Rajaratnam SMW, Sletten TL. Pilot feasibility testing of biomathematical model recommendations for personalising sleep timing in shift workers. J Sleep Res 2023:e14026. [PMID: 37632717 DOI: 10.1111/jsr.14026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/02/2023] [Accepted: 08/04/2023] [Indexed: 08/28/2023]
Abstract
Sleep disturbances and circadian disruption play a central role in adverse health, safety, and performance outcomes in shift workers. While biomathematical models of sleep and alertness can be used to personalise interventions for shift workers, their practical implementation is undertested. This study tested the feasibility of implementing two biomathematical models-the Phillips-Robinson Model and the Model for Arousal Dynamics-in 28 shift-working nurses, 14 in each group. The study examined the overlap and adherence between model recommendations and sleep behaviours, and changes in sleep following the implementation of recommendations. For both groups combined, the mean (SD) percentage overlap between when a model recommended an individual to sleep and when sleep was obtained was 73.62% (10.24%). Adherence between model recommendations and sleep onset and offset times was significantly higher with the Model of Arousal Dynamics compared to the Phillips-Robinson Model. For the Phillips-Robinson model, 27% of sleep onset and 35% of sleep offset times were within ± 30 min of model recommendations. For the Model of Arousal Dynamics, 49% of sleep onset, and 35% of sleep offset times were within ± 30 min of model recommendations. Compared to pre-study, significant improvements were observed post-study for sleep disturbance (Phillips-Robinson Model), and insomnia severity and sleep-related impairments (Model of Arousal Dynamics). Participants reported that using a digital, automated format for the delivery of sleep recommendations would enable greater uptake. These findings provide a positive proof-of-concept for using biomathematical models to recommend sleep in operational contexts.
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Affiliation(s)
- Prerna Varma
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Australia
| | | | - Andrew J K Phillips
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Australia
| | - Stuart Knock
- School of Physics, The University of Sydney, Camperdown, Australia
| | - Mark E Howard
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Australia
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Australia
- Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Australia
| | - Shantha M W Rajaratnam
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Australia
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Tracey L Sletten
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Australia
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7
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Harris R, Beatty CJ, Cori JM, Spitz G, Soleimanloo SS, Peterson SA, Naqvi A, Barnes M, Downey LA, Shiferaw BA, Anderson C, Tucker AJ, Clark A, Rajaratnam SMW, Howard ME, Sletten TL, Wolkow AP. The impact of break duration, time of break onset, and prior shift duration on the amount of sleep between shifts in heavy vehicle drivers. J Sleep Res 2023; 32:e13730. [PMID: 36193767 DOI: 10.1111/jsr.13730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/16/2022] [Accepted: 08/31/2022] [Indexed: 11/28/2022]
Abstract
This study aimed to examine the impact of break duration between consecutive shifts, time of break onset, and prior shift duration on total sleep time (TST) between shifts in heavy vehicle drivers (HVDs), and to assess the interaction between break duration and time of break onset. The sleep (actigraphy and sleep diaries) and work shifts (work diaries) of 27 HVDs were monitored during their usual work schedule for up to 9 weeks. Differences in TST between consecutive shifts and days off were assessed. Linear mixed models (followed by pairwise comparisons) assessed whether break duration, prior shift duration, time of break onset, and the interaction between break duration and break onset were related to TST between shifts. Investigators found TST between consecutive shifts (mean [SD] 6.38 [1.38] h) was significantly less than on days off (mean [SD] 7.63 [1.93] h; p < 0.001). Breaks starting between 12:01 and 8:00 a.m. led to shorter sleep (p < 0.05) compared to breaks starting between 4:01 and 8:00 p.m. Break durations up to 7, 9, and 11 h (Australian and European minimum break durations) resulted in a mean (SD) of 4.76 (1.06), 5.66 (0.77), and 6.41 (1.06) h of sleep, respectively. The impact of shift duration prior to the break and the interaction between break duration and time of break were not significant. HVDs' sleep between workdays is influenced independently by break duration and time of break onset. This naturalistic study provides evidence that current break regulations prevent sufficient sleep duration in this industry. Work regulations should evaluate appropriate break durations and break onset times to allow longer sleep opportunities for HVDs.
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Affiliation(s)
- Rachael Harris
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Caroline J Beatty
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia
| | - Jennifer M Cori
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia
| | - Gershon Spitz
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Shamsi Shekari Soleimanloo
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia.,Institute for Social Science Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Scott A Peterson
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
| | - Aqsa Naqvi
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia
| | - Maree Barnes
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia.,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
| | - Luke A Downey
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Centre for Human Psychopharmacology, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Brook A Shiferaw
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Centre for Human Psychopharmacology, Swinburne University of Technology, Hawthorn, Victoria, Australia.,Seeing Machines Ltd., Fyshwick, Australian Capital Territory, Australia
| | - Clare Anderson
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
| | - Andrew J Tucker
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
| | - Anna Clark
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
| | - Shantha M W Rajaratnam
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
| | - Mark E Howard
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia.,Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
| | - Tracey L Sletten
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
| | - Alexander P Wolkow
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
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Murray JM, Magee M, Giliberto ES, Booker LA, Tucker AJ, Galaska B, Sibenaller SM, Baer SA, Postnova S, Sondag TA, Phillips AJ, Sletten TL, Howard ME, Rajaratnam SM. Mobile app for personalized sleep–wake management for shift workers: A user testing trial. Digit Health 2023; 9:20552076231165972. [PMID: 37009306 PMCID: PMC10064476 DOI: 10.1177/20552076231165972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 03/10/2023] [Indexed: 04/01/2023] Open
Abstract
Objective Development of personalized sleep–wake management tools is critical to improving sleep and functional outcomes for shift workers. The objective of the current study was to test the performance, engagement and usability of a mobile app ( SleepSync) for personalized sleep–wake management in shift workers that aid behavioural change and provide practical advice by providing personalized sleep scheduling recommendations and education. Methods Shift workers ( n = 27; 20 healthcare and 7 from other industries) trialled the mobile app for two weeks to determine performance, engagement and usability. Primary outcomes were self-reported total sleep time, ability to fall asleep, sleep quality and perception of overall recovery on days off. Secondary performance outcomes included sleep disturbances (insomnia and sleep hygiene symptoms, and sleep-related impairments) and mood (anxiety, stress and depression) pre- and post-app use. Satisfaction with schedule management, integration into daily routine and influence on behaviour were used to determine engagement, while the usability was assessed for functionality and ease of use of features. Results Total sleep time ( P = .04), ability to fall asleep ( P < .001), quality of sleep ( P = .001), insomnia ( P = .02), sleep hygiene ( P = .01), sleep-related impairments ( P = .001), anxiety ( P = .001), and stress ( P = .006) were all improved, with non-significant improvements in recovery on days off ( P = .19) and depression ( P = .07). All measures of engagement and usability were scored positively by the majority of users. Conclusions This pilot trial provides preliminary evidence of the positive impact of the SleepSync app in improving sleep and mood outcomes in shift workers, and warrants confirmation in a larger controlled trial.
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Affiliation(s)
- Jade M. Murray
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Australia
| | - Michelle Magee
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Australia
| | - Emma S. Giliberto
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Australia
| | - Lauren A. Booker
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Australia
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Australia
| | - Andrew J. Tucker
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Australia
| | - Beth Galaska
- Philips RS North America LLC f/k/a Respironics Inc, Murrysville, USA
| | | | - Sharon A. Baer
- Philips RS North America LLC f/k/a Respironics Inc, Murrysville, USA
| | - Svetlana Postnova
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Australia
- School of Physics, University of Sydney, Sydney, Australia
| | | | - Andrew J.K. Phillips
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Australia
| | - Tracey L. Sletten
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Australia
| | - Mark E. Howard
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Australia
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Australia
| | - Shantha M.W. Rajaratnam
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Australia
- Shantha M.W. Rajaratnam, Turner Institute for Brain and Mental Health, School of Psychological Sciences, 18 Innovation Walk, Monash University, Clayton, Victoria 3800, Australia.
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9
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Sletten TL, Sullivan JP, Arendt J, Palinkas LA, Barger LK, Fletcher L, Arnold M, Wallace J, Strauss C, Baker RJS, Kloza K, Kennaway DJ, Rajaratnam SMW, Ayton J, Lockley SW. The role of circadian phase in sleep and performance during Antarctic winter expeditions. J Pineal Res 2022; 73:e12817. [PMID: 35833316 PMCID: PMC9541096 DOI: 10.1111/jpi.12817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 06/23/2022] [Accepted: 07/06/2022] [Indexed: 11/29/2022]
Abstract
The Antarctic environment presents an extreme variation in the natural light-dark cycle which can cause variability in the alignment of the circadian pacemaker with the timing of sleep, causing sleep disruption, and impaired mood and performance. This study assessed the incidence of circadian misalignment and the consequences for sleep, cognition, and psychological health in 51 over-wintering Antarctic expeditioners (45.6 ± 11.9 years) who completed daily sleep diaries, and monthly performance tests and psychological health questionnaires for 6 months. Circadian phase was assessed via monthly 48-h urine collections to assess the 6-sulphatoxymelatonin (aMT6s) rhythm. Although the average individual sleep duration was 7.2 ± 0.8 h, there was substantial sleep deficiency with 41.4% of sleep episodes <7 h and 19.1% <6 h. Circadian phase was highly variable and 34/50 expeditioners had sleep episodes that occurred at an abnormal circadian phase (acrophase outside of the sleep episode), accounting for 18.8% (295/1565) of sleep episodes. Expeditioners slept significantly less when misaligned (6.1 ± 1.3 h), compared with when aligned (7.3 ± 1.0 h; p < .0001). Performance and mood were worse when awake closer to the aMT6s peak and with increased time awake (all p < .0005). This research highlights the high incidence of circadian misalignment in Antarctic over-wintering expeditioners. Similar incidence has been observed in long-duration space flight, reinforcing the fidelity of Antarctica as a space analog. Circadian misalignment has considerable safety implications, and potentially longer term health risks for other circadian-controlled physiological systems. This increased risk highlights the need for preventative interventions, such as proactively planned lighting solutions, to ensure circadian alignment during long-duration Antarctic and space missions.
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Affiliation(s)
- Tracey L. Sletten
- Turner Institute for Brain and Mental Health and School of Psychological SciencesMonash UniversityVictoriaAustralia
| | - Jason P. Sullivan
- Division of Sleep and Circadian Disorders, Departments of Medicine and NeurologyBrigham and Women's HospitalBostonMassachusettsUSA
| | - Josephine Arendt
- Faculty of Health and Medical SciencesUniversity of SurreyGuildfordSurreyUK
| | - Lawrence A. Palinkas
- Suzanne Dworak‐Peck School of Social WorkUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Laura K. Barger
- Turner Institute for Brain and Mental Health and School of Psychological SciencesMonash UniversityVictoriaAustralia
- Division of Sleep and Circadian Disorders, Departments of Medicine and NeurologyBrigham and Women's HospitalBostonMassachusettsUSA
- Division of Sleep Medicine, Harvard Medical SchoolBostonMassachusettsUSA
| | - Lloyd Fletcher
- Polar Medicine Unit, Australian Antarctic DivisionKingstonTasmaniaAustralia
| | - Malcolm Arnold
- Polar Medicine Unit, Australian Antarctic DivisionKingstonTasmaniaAustralia
| | - Jan Wallace
- Polar Medicine Unit, Australian Antarctic DivisionKingstonTasmaniaAustralia
| | - Clive Strauss
- Polar Medicine Unit, Australian Antarctic DivisionKingstonTasmaniaAustralia
| | | | - Kate Kloza
- Polar Medicine Unit, Australian Antarctic DivisionKingstonTasmaniaAustralia
| | - David J. Kennaway
- Robinson Research Institute, School of Medicine, Discipline of Obstetrics and GynaecologyUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - Shantha M. W. Rajaratnam
- Turner Institute for Brain and Mental Health and School of Psychological SciencesMonash UniversityVictoriaAustralia
- Division of Sleep and Circadian Disorders, Departments of Medicine and NeurologyBrigham and Women's HospitalBostonMassachusettsUSA
- Division of Sleep Medicine, Harvard Medical SchoolBostonMassachusettsUSA
| | - Jeff Ayton
- Polar Medicine Unit, Australian Antarctic DivisionKingstonTasmaniaAustralia
| | - Steven W. Lockley
- Division of Sleep and Circadian Disorders, Departments of Medicine and NeurologyBrigham and Women's HospitalBostonMassachusettsUSA
- Division of Sleep Medicine, Harvard Medical SchoolBostonMassachusettsUSA
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10
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Rogers M, Coates A, Huggins CE, Dorrian J, Clark AB, Davis C, Leung GK, Davis R, Phoi YY, Kellow NJ, Iacovou M, Yates CL, Banks S, Sletten TL, Bonham MP. Study protocol for the Shifting Weight using Intermittent Fasting in night shift workers (SWIFt) study: a three-arm randomised controlled trial comparing three weight loss strategies in night shift workers with obesity. BMJ Open 2022; 12:e060520. [PMID: 35473743 PMCID: PMC9045043 DOI: 10.1136/bmjopen-2021-060520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
INTRODUCTION Shift workers are at an increased risk of developing obesity and type 2 diabetes. Eating and sleeping out of synchronisation with endogenous circadian rhythms causes weight gain, hyperglycaemia and insulin resistance. Interventions that promote weight loss and reduce the metabolic consequences of eating at night are needed for night shift workers. The aim of this study is to examine the effects of three weight loss strategies on weight loss and insulin resistance (HOMA-IR) in night shift workers. METHODS AND ANALYSIS A multisite 18-month, three-arm randomised controlled trial comparing three weight loss strategies; continuous energy restriction; and two intermittent fasting strategies whereby participants will fast for 2 days per week (5:2); either during the day (5:2D) or during the night shift (5:2N). Participants will be randomised to a weight loss strategy for 24 weeks (weight loss phase) and followed up 12 months later (maintenance phase). The primary outcomes are weight loss and a change in HOMA-IR. Secondary outcomes include changes in glucose, insulin, blood lipids, body composition, waist circumference, physical activity and quality of life. Assessments will be conducted at baseline, 24 weeks (primary endpoint) and 18 months (12-month follow-up). The intervention will be delivered by research dietitians via a combination of face-to-face and telehealth consultations. Mixed-effect models will be used to identify changes in dependent outcomes (weight and HOMA-IR) with predictor variables of outcomes of group, time and group-time interaction, following an intention-to-treat approach. ETHICS AND DISSEMINATION The study protocol was approved by Monash Health Human Research Ethics Committee (RES 19-0000-462A) and registered with Monash University Human Research Ethics Committee. Ethical approval has also been obtained from the University of South Australia (HREC ID: 202379) and Ambulance Victoria Research Committee (R19-037). Results from this trial will be disseminated via conference presentations, peer-reviewed journals and student theses. TRIAL REGISTRATION NUMBER Australian New Zealand Clinical Trials Registry (ACTRN-12619001035112).
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Affiliation(s)
- Michelle Rogers
- UniSA Justice & Society, University of South Australia, Adelaide, South Australia, Australia
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), University of South Australia, Adelaide, South Australia, Australia
| | - Alison Coates
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), University of South Australia, Adelaide, South Australia, Australia
- Allied Health and Human Performance, University of South Australia, Adelaide, South Australia, Australia
| | - Catherine E Huggins
- Institute for Health Transformation, Deakin University, Burwood, Victoria, Australia
| | - Jillian Dorrian
- UniSA Justice & Society, University of South Australia, Adelaide, South Australia, Australia
| | - Angela B Clark
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
| | - Corinne Davis
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
| | - Gloria Kw Leung
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
| | - Rochelle Davis
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
| | - Yan Yin Phoi
- Alliance for Research in Exercise, Nutrition and Activity (ARENA), University of South Australia, Adelaide, South Australia, Australia
- Allied Health and Human Performance, University of South Australia, Adelaide, South Australia, Australia
| | - Nicole J Kellow
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
| | - Marina Iacovou
- Centre of Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Molecular and Translational Science, Monash University, Clayton, Victoria, Australia
| | - Crystal L Yates
- UniSA Justice & Society, University of South Australia, Adelaide, South Australia, Australia
- Behaviour-Brain-Body Research Centre, University of South Australia, Adelaide, South Australia, Australia
| | - Siobhan Banks
- UniSA Justice & Society, University of South Australia, Adelaide, South Australia, Australia
- Behaviour-Brain-Body Research Centre, University of South Australia, Adelaide, South Australia, Australia
| | - Tracey L Sletten
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Notting Hill, Victoria, Australia
| | - Maxine P Bonham
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
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11
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Ganesan S, Manousakis JE, Mulhall MD, Sletten TL, Tucker A, Howard ME, Anderson C, Rajaratnam SMW. Sleep, alertness and performance across a first and a second night shift in mining haul truck drivers. Chronobiol Int 2022; 39:769-780. [PMID: 35176952 DOI: 10.1080/07420528.2022.2034838] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This study examined the impact of first and second night shift work on sleep and performance in mining haul truck drivers. Sleep-wake patterns were monitored using wrist actigraphy. The Karolinska Sleepiness Scale (KSS), Psychomotor Vigilance Test (PVT) and a truck simulator were administered at the start and end of the first (N1) or second (N2) night shift (19:00-07:00 h). Participants were categorised into those who demonstrated a decline in performance (increase of one or more PVT lapses [reaction time >500 msec] from the start to the end of shift) or those who did not demonstrate a decline in performance (no increase in lapses) from the start to the end of shift. Total sleep time (TST) was longer in the 24 h prior to N1 (9.05 ± 1.49 h) compared to N2 (5.38 ± 1.32 h). PVT lapses and the slowest 10% of reaction times were similar at the start and end of N1, while greater impairments on these outcomes were observed at the end of N2 compared to the end of N1 (p < .05). In contrast, subjective sleepiness was equally impaired at the end of both night shifts. PVT performance (lapses and slowest 10% of reaction times) and drive violations demonstrated a similar direction of change on N1 and N2. Participants who demonstrated a decline in performance showed reduced TST in the 48 h prior to shifts compared to those who demonstrated no decline in performance across the shift. Likely due to short sleep prior, the end of N2 was associated with pronounced performance impairments on the PVT and drive violations compared to the start of the shift. The findings suggest that drive violations may be more sensitive to sleep loss compared to the other driving measures examined in this study. This study also emphasizes the need for adequate recovery sleep between night shifts.
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Affiliation(s)
- Saranea Ganesan
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Australia
| | - Jessica E Manousakis
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia
| | - Megan D Mulhall
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Australia
| | - Tracey L Sletten
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Australia
| | - Andrew Tucker
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Australia
| | - Mark E Howard
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Australia.,Institute for Breathing and Sleep, Austin Health, Heidelberg, Australia
| | - Clare Anderson
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Australia
| | - Shantha M W Rajaratnam
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Australia
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12
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Booker LA, Sletten TL, Barnes M, Alvaro P, Collins A, Chai-Coetzer CL, McMahon M, Lockley SW, Rajaratnam SMW, Howard ME. The effectiveness of an individualized sleep and shift work education and coaching program to manage shift work disorder in nurses: a randomized controlled trial. J Clin Sleep Med 2021; 18:1035-1045. [PMID: 34870586 DOI: 10.5664/jcsm.9782] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
STUDY OBJECTIVES While insomnia and sleepiness symptoms are common in shift workers, 20-30% experience more severe symptoms and meet the criteria for shift work disorder (SWD). SWD can lead to impairments in cognitive function, physical and mental health, and reduced productivity and increased risk of workplace injury. The aim of this study was to deliver and evaluate a shift work individual management coaching program, focusing on sleep education, promoting good sleep hygiene, and providing individualized behavioral strategies to cope with shift schedules. METHODS A clustered randomized controlled trial of sleep education and sleep disorders screening was undertaken, based on hospital wards at a tertiary hospital in Melbourne, Australia. Participants identified as high risk for SWD underwent one of two 8-week programs; a shift work individualized management program (S.W.I.M.) or an active control. The primary outcome was ward-based sick leave. Secondary outcomes were SWD risk, sleep hygiene, insomnia, depression, and anxiety. A total of 149 nurses, across 16 wards (96% female, 34.66 ± 11.99 years) completed both baseline and follow-up questionnaires (23.9% were high risk SWD). RESULTS There was no significant reduction in sick leave between intervention and control wards (mean difference=1.2 days, p=.063). Improvements were seen in insomnia (p<.0001*), and depression (intervention, p=<.0001*, control, p=.023) in both groups, but were not significantly different between programs. Anxiety (p=.001. control p=.079) and FOSQ (p=.001 control p=.056) improved only for the intervention. CONCLUSIONS This SWD intervention trial did not reduce sick leave compared to the active control but there was an improvement. Improvements in sleep hygiene, insomnia, depression, and anxiety severity were seen for both groups. Future intervention trials should consider including both sleep and mental health interventions, strategies to avoid between group contamination and the duration of programs for optimal behavioral modification. CLINICAL TRIAL REGISTRATION Registry: Australian New Zealand Clinical Trials Registry; Identifier: ACTRN12616000369426.
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Affiliation(s)
- Lauren A Booker
- Turner Institute for Brain and Mental Health, School of Psychological Sciences Monash University, Clayton, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia.,Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,University Department of Rural Health, La Trobe Rural Health School, La Trobe University, Bendigo, Victoria, Australia
| | - Tracey L Sletten
- Turner Institute for Brain and Mental Health, School of Psychological Sciences Monash University, Clayton, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia
| | - Maree Barnes
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,University of Melbourne, Parkville, Victoria Australia
| | - Pasquale Alvaro
- Flinders University, School of Psychology, Adelaide, SA, Australia
| | - Allison Collins
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Ching Li Chai-Coetzer
- Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Flinders University, SA, Australia.,Respiratory and Sleep Services, Southern Adelaide Local Health Network, SA Health, SA, Australia
| | - Marcus McMahon
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Steven W Lockley
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts.,Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts
| | - Shantha M W Rajaratnam
- Turner Institute for Brain and Mental Health, School of Psychological Sciences Monash University, Clayton, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts.,Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts
| | - Mark E Howard
- Turner Institute for Brain and Mental Health, School of Psychological Sciences Monash University, Clayton, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia.,Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,University of Melbourne, Parkville, Victoria Australia
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13
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Tymms K, Butcher BE, Sletten TL, Smith T, O'Sullivan C, Littlejohn G, Sadler R, Tronnberg R, Griffiths H. Prevalence of sleep disturbance and the association between poor disease control in people with ankylosing spondylitis within the Australian clinical setting (ASLEEP study): a real-world observational study using the OPAL dataset. Clin Rheumatol 2021; 41:1105-1114. [PMID: 34825268 PMCID: PMC8913462 DOI: 10.1007/s10067-021-05953-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/27/2021] [Accepted: 09/30/2021] [Indexed: 11/08/2022]
Abstract
Introduction Sleep disturbance and fatigue are commonly reported in ankylosing spondylitis (AS) but specific prevalence and the relationship to disease control are unknown. Method This retrospective non-interventional observational study of data from the OPAL dataset included patients with AS (ICD code M45, M45.0 or M08.1), aged 18 to 95 years and had completed ≥ 1 sleep questionnaire between 1 January 2019 and 30 September 2020. The prevalence of insomnia and obstructive sleep apnoea were assessed using the Insomnia Severity Index (ISI) and Multivariate Apnoea Prediction Index (MAPI), respectively. Propensity score (PS) matching based on sex, age and symptom duration increased comparability between patients administered tumour necrosis factor inhibitors (TNFi) and interleukin 17A inhibitors (IL-17Ai). Results Four hundred ninety-five patients were included. The mean ISI total score in the overall population was 8.6 ± 6.2. Self-reported moderate or severe clinical insomnia was present in 16% and 3.2% of patients, respectively. The mean MAPI score was 0.4 ± 0.3, self-reported apnoea was identified in 31.5% of patients and the mean FACIT-Fatigue score was 36.1 ± 10.7. In the PS matched population, the only treatment-related difference was the mean MAPI score (IL-17Ai 0.4 ± 0.3 and TNFi 0.3 ± 0.2, p = 0.046). Those with poor disease control (BASDAI ≥ 4) were more likely (odds ratio [OR] 7.29, 95% CI 2.37 to 22.46, p = 0.001) to have a greater severity of insomnia symptoms than those with good disease control. Conclusion In this real-world AS cohort, poor disease control was associated with sleep disturbance. Little difference in sleep disturbance was observed between biologic TNFi and IL-17Ai treatment. Key Points | • Sleep disturbance and fatigue are common in patients with ankylosing spondylitis. • In our real-world cohort, self-reported apnoea was reported in one-third of patients; and one in five patients reported moderate to severe insomnia. • Those with poor disease control were more likely to experience greater sleep disturbance than those with good disease control. |
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Affiliation(s)
- Kathleen Tymms
- OPAL Rheumatology Ltd, Sydney, NSW, Australia. .,Canberra Rheumatology, 9/40 Marcus Clarke St, Canberra, ACT, 2601, Australia.
| | - Belinda E Butcher
- University of New South Wales, Kensington, NSW, Australia.,WriteSource Medical Pty Ltd, Lane Cove, NSW, Australia
| | - Tracey L Sletten
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, VIC, Australia
| | - Tegan Smith
- OPAL Rheumatology Ltd, Sydney, NSW, Australia
| | | | - Geoffrey Littlejohn
- OPAL Rheumatology Ltd, Sydney, NSW, Australia.,Department of Medicine, Monash University, Clayton, VIC, Australia
| | - Ricky Sadler
- Novartis Pharmaceuticals Australia Pty Ltd, Macquarie Park, NSW, Australia
| | - Rebecca Tronnberg
- Novartis Pharmaceuticals Australia Pty Ltd, Macquarie Park, NSW, Australia
| | - Hedley Griffiths
- OPAL Rheumatology Ltd, Sydney, NSW, Australia.,Barwon Rheumatology Service, Geelong, VIC, Australia
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14
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Knock SA, Magee M, Stone JE, Ganesan S, Mulhall MD, Lockley SW, Howard ME, Rajaratnam SMW, Sletten TL, Postnova S. Prediction of shiftworker alertness, sleep, and circadian phase using a model of arousal dynamics constrained by shift schedules and light exposure. Sleep 2021; 44:zsab146. [PMID: 34111278 PMCID: PMC8598188 DOI: 10.1093/sleep/zsab146] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 04/13/2021] [Indexed: 11/13/2022] Open
Abstract
STUDY OBJECTIVES The study aimed to, for the first time, (1) compare sleep, circadian phase, and alertness of intensive care unit (ICU) nurses working rotating shifts with those predicted by a model of arousal dynamics; and (2) investigate how different environmental constraints affect predictions and agreement with data. METHODS The model was used to simulate individual sleep-wake cycles, urinary 6-sulphatoxymelatonin (aMT6s) profiles, subjective sleepiness on the Karolinska Sleepiness Scale (KSS), and performance on a Psychomotor Vigilance Task (PVT) of 21 ICU nurses working day, evening, and night shifts. Combinations of individual shift schedules, forced wake time before/after work and lighting, were used as inputs to the model. Predictions were compared to empirical data. Simulations with self-reported sleep as an input were performed for comparison. RESULTS All input constraints produced similar prediction for KSS, with 56%-60% of KSS scores predicted within ±1 on a day and 48%-52% on a night shift. Accurate prediction of an individual's circadian phase required individualized light input. Combinations including light information predicted aMT6s acrophase within ±1 h of the study data for 65% and 35%-47% of nurses on diurnal and nocturnal schedules. Minute-by-minute sleep-wake state overlap between the model and the data was between 81 ± 6% and 87 ± 5% depending on choice of input constraint. CONCLUSIONS The use of individualized environmental constraints in the model of arousal dynamics allowed for accurate prediction of alertness, circadian phase, and sleep for more than half of the nurses. Individual differences in physiological parameters will need to be accounted for in the future to further improve predictions.
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Affiliation(s)
- Stuart A Knock
- School of Physics, the University of Sydney, Camperdown, NSW, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, VIC, Australia
| | - Michelle Magee
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, VIC, Australia
- Turner Institute for Brain and Mental Health, Monash University, Clayton, VIC, Australia
| | - Julia E Stone
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, VIC, Australia
- Turner Institute for Brain and Mental Health, Monash University, Clayton, VIC, Australia
| | - Saranea Ganesan
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, VIC, Australia
- Turner Institute for Brain and Mental Health, Monash University, Clayton, VIC, Australia
| | - Megan D Mulhall
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, VIC, Australia
- Turner Institute for Brain and Mental Health, Monash University, Clayton, VIC, Australia
| | - Steven W Lockley
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, VIC, Australia
- Turner Institute for Brain and Mental Health, Monash University, Clayton, VIC, Australia
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Mark E Howard
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, VIC, Australia
- Turner Institute for Brain and Mental Health, Monash University, Clayton, VIC, Australia
- Institute for Breathing and Sleep, Austin Health, Heidelberg, VIC, Australia
| | - Shantha M W Rajaratnam
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, VIC, Australia
- Turner Institute for Brain and Mental Health, Monash University, Clayton, VIC, Australia
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Tracey L Sletten
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, VIC, Australia
- Turner Institute for Brain and Mental Health, Monash University, Clayton, VIC, Australia
| | - Svetlana Postnova
- School of Physics, the University of Sydney, Camperdown, NSW, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, VIC, Australia
- Sydney Nano, the University of Sydney, Camperdown, NSW, Australia
- Woolcock Institute of Medical Research, Glebe, NSW, Australia
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15
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Cori JM, Downey LA, Sletten TL, Beatty CJ, Shiferaw BA, Soleimanloo SS, Turner S, Naqvi A, Barnes M, Kuo J, Lenné MG, Anderson C, Tucker AJ, Wolkow AP, Clark A, Rajaratnam SMW, Howard ME. The impact of 7-hour and 11-hour rest breaks between shifts on heavy vehicle truck drivers' sleep, alertness and naturalistic driving performance. Accid Anal Prev 2021; 159:106224. [PMID: 34192654 DOI: 10.1016/j.aap.2021.106224] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 04/01/2021] [Accepted: 05/27/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND An inadequate rest break between shifts may contribute to driver sleepiness. This study assessed whether extending the major rest break between shifts from 7-hours (Australian industry standard) to 11-hours, improved drivers' sleep, alertness and naturalistic driving performance. METHODS 17 heavy vehicle drivers (16 male) were recruited to complete two conditions. Each condition comprised two 13-hour shifts, separated by either a 7- or 11-hour rest break. The initial 13-hour shift was the drivers' regular work. The rest break and following 13-hour shift were simulated. The simulated shift included 5-hours of naturalistic driving with measures of subjective sleepiness, physiological alertness (ocular and electroencephalogram) and performance (steering and lane departures). RESULTS 13 drivers provided useable data. Total sleep during the rest break was greater in the 11-hour than the 7-hour condition (median hours [25th to 75th percentile] 6.59 [6.23, 7.23] vs. 5.07 [4.46, 5.38], p = 0.008). During the simulated shift subjective sleepiness was marginally better for the 11-hour condition (mean Karolinska Sleepiness Scale [95th CI] = 4.52 [3.98, 5.07] vs. 5.12 [4.56, 5.68], p = 0.009). During the drive, ocular and vehicle metrics were improved for the 11-hour condition (p<0.05). Contrary to expectations, mean lane departures p/hour were increased during the 11-hour condition (1.34 [-0.38,3.07] vs. 0.63 [-0.2,1.47], p = 0.027). CONCLUSIONS Extending the major rest between shifts substantially increases sleep duration and has a modest positive impact on driver alertness and performance. Future work should replicate the study in a larger sample size to improve generalisability and assess the impact of consecutive 7-hour major rest breaks.
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Affiliation(s)
- Jennifer M Cori
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia; Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia; Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia.
| | - Luke A Downey
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia; Centre for Human Psychopharmacology, Swinburne University of Technology, Hawthorn, Australia
| | - Tracey L Sletten
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia
| | - Caroline J Beatty
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia; Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia; Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Brook A Shiferaw
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia; Centre for Human Psychopharmacology, Swinburne University of Technology, Hawthorn, Australia; Seeing Machines Ltd., 80 Mildura St., Fyshwick, ACT, Australia
| | - Shamsi Shekari Soleimanloo
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia; Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia; Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia; Institute for Social Science Research, The University of Queensland, Queensland, Australia
| | - Sophie Turner
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia; Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia; Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Aqsa Naqvi
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia; Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia
| | - Maree Barnes
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia; Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia; Department of Medicine, University of Melbourne, Australia
| | - Jonny Kuo
- Seeing Machines Ltd., 80 Mildura St., Fyshwick, ACT, Australia
| | - Michael G Lenné
- Seeing Machines Ltd., 80 Mildura St., Fyshwick, ACT, Australia
| | - Clare Anderson
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia
| | - Andrew J Tucker
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia
| | - Alexander P Wolkow
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia
| | - Anna Clark
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia
| | - Shantha M W Rajaratnam
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia
| | - Mark E Howard
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia; Department of Respiratory and Sleep Medicine, Austin Health, Heidelberg, Victoria, Australia; Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia; Department of Medicine, University of Melbourne, Australia
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16
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Weaver MD, Sletten TL, Foster RG, Gozal D, Klerman EB, Rajaratnam SMW, Roenneberg T, Takahashi JS, Turek FW, Vitiello MV, Young MW, Czeisler CA. Adverse impact of polyphasic sleep patterns in humans: Report of the National Sleep Foundation sleep timing and variability consensus panel. Sleep Health 2021; 7:293-302. [PMID: 33795195 DOI: 10.1016/j.sleh.2021.02.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 01/02/2023]
Abstract
Polyphasic sleep is the practice of distributing multiple short sleep episodes across the 24-hour day rather than having one major and possibly a minor ("nap") sleep episode each day. While the prevalence of polyphasic sleep is unknown, anecdotal reports suggest attempts to follow this practice are common, particularly among young adults. Polyphasic-sleep advocates claim to thrive on as little as 2 hours of total sleep per day. However, significant concerns have been raised that polyphasic sleep schedules can result in health and safety consequences. We reviewed the literature to identify the impact of polyphasic sleep schedules (excluding nap or siesta schedules) on health, safety, and performance outcomes. Of 40,672 potentially relevant publications, with 2,023 selected for full-text review, 22 relevant papers were retained. We found no evidence supporting benefits from following polyphasic sleep schedules. Based on the current evidence, the consensus opinion is that polyphasic sleep schedules, and the sleep deficiency inherent in those schedules, are associated with a variety of adverse physical health, mental health, and performance outcomes. Striving to adopt a schedule that significantly reduces the amount of sleep per 24 hours and/or fragments sleep into multiple episodes throughout the 24-hour day is not recommended.
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Affiliation(s)
- Matthew D Weaver
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Tracey L Sletten
- Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Australia
| | - Russell G Foster
- Sleep & Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - David Gozal
- Department of Child Health, University of Missouri, Columbia, Missouri, USA
| | - Elizabeth B Klerman
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA; Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Shantha M W Rajaratnam
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA; Turner Institute for Brain and Mental Health and School of Psychological Sciences, Monash University, Clayton, Australia
| | - Till Roenneberg
- Institute for Medical Psychology, Ludwig Maximilian University of Munich, Munich, Germany
| | - Joseph S Takahashi
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, Texas, USA; Howard Hughes Medical Institute, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Fred W Turek
- Center for Sleep and Circadian Biology, Department of Neurobiology, Northwestern University, Evanston, Illinois, USA
| | - Michael V Vitiello
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington, USA
| | - Michael W Young
- Laboratory of Genetics, The Rockefeller University, New York, New York, USA
| | - Charles A Czeisler
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA.
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17
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Murray JM, Magee M, Sletten TL, Gordon C, Lovato N, Ambani K, Bartlett DJ, Kennaway DJ, Lack LC, Grunstein RR, Lockley SW, Rajaratnam SMW, Phillips AJK. Light-based methods for predicting circadian phase in delayed sleep-wake phase disorder. Sci Rep 2021; 11:10878. [PMID: 34035333 PMCID: PMC8149449 DOI: 10.1038/s41598-021-89924-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 04/13/2021] [Indexed: 02/04/2023] Open
Abstract
Methods for predicting circadian phase have been developed for healthy individuals. It is unknown whether these methods generalize to clinical populations, such as delayed sleep-wake phase disorder (DSWPD), where circadian timing is associated with functional outcomes. This study evaluated two methods for predicting dim light melatonin onset (DLMO) in 154 DSWPD patients using ~ 7 days of sleep-wake and light data: a dynamic model and a statistical model. The dynamic model has been validated in healthy individuals under both laboratory and field conditions. The statistical model was developed for this dataset and used a multiple linear regression of light exposure during phase delay/advance portions of the phase response curve, as well as sleep timing and demographic variables. Both models performed comparably well in predicting DLMO. The dynamic model predicted DLMO with root mean square error of 68 min, with predictions accurate to within ± 1 h in 58% of participants and ± 2 h in 95%. The statistical model predicted DLMO with root mean square error of 57 min, with predictions accurate to within ± 1 h in 75% of participants and ± 2 h in 96%. We conclude that circadian phase prediction from light data is a viable technique for improving screening, diagnosis, and treatment of DSWPD.
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Affiliation(s)
- Jade M. Murray
- grid.1002.30000 0004 1936 7857Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, 18 Innovation Walk, Clayton, VIC 3800 Australia ,Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, VIC Australia ,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, NSW Australia
| | - Michelle Magee
- grid.1002.30000 0004 1936 7857Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, 18 Innovation Walk, Clayton, VIC 3800 Australia ,Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, VIC Australia ,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, NSW Australia ,grid.1008.90000 0001 2179 088XCentre for Neuroscience of Speech, Department of Audiology and Speech Pathology, University of Melbourne, Melbourne, VIC Australia
| | - Tracey L. Sletten
- grid.1002.30000 0004 1936 7857Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, 18 Innovation Walk, Clayton, VIC 3800 Australia ,Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, VIC Australia ,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, NSW Australia
| | - Christopher Gordon
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, VIC Australia ,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, NSW Australia ,grid.417229.b0000 0000 8945 8472Woolcock Institute of Medical Research and Sydney Local Health District, Sydney, NSW Australia ,grid.1013.30000 0004 1936 834XUniversity of Sydney Susan Wakil School of Nursing, Camperdown, NSW Australia
| | - Nicole Lovato
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, VIC Australia ,grid.1014.40000 0004 0367 2697Adelaide Institute for Sleep Health, College of Medicine and Public Health, Flinders University, Adelaide, SA Australia
| | - Krutika Ambani
- grid.1002.30000 0004 1936 7857Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, 18 Innovation Walk, Clayton, VIC 3800 Australia
| | - Delwyn J. Bartlett
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, VIC Australia ,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, NSW Australia ,grid.417229.b0000 0000 8945 8472Woolcock Institute of Medical Research and Sydney Local Health District, Sydney, NSW Australia
| | - David J. Kennaway
- grid.1010.00000 0004 1936 7304Robinson Research Institute and School of Medicine, University of Adelaide, Adelaide, SA Australia
| | - Leon C. Lack
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, VIC Australia ,grid.1014.40000 0004 0367 2697Adelaide Institute for Sleep Health, College of Medicine and Public Health, Flinders University, Adelaide, SA Australia
| | - Ronald R. Grunstein
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, VIC Australia ,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, NSW Australia ,grid.417229.b0000 0000 8945 8472Woolcock Institute of Medical Research and Sydney Local Health District, Sydney, NSW Australia
| | - Steven W. Lockley
- grid.1002.30000 0004 1936 7857Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, 18 Innovation Walk, Clayton, VIC 3800 Australia ,Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, VIC Australia ,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, NSW Australia ,grid.62560.370000 0004 0378 8294Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA USA ,grid.38142.3c000000041936754XDivision of Sleep Medicine, Harvard Medical School, Boston, MA USA
| | - Shantha M. W. Rajaratnam
- grid.1002.30000 0004 1936 7857Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, 18 Innovation Walk, Clayton, VIC 3800 Australia ,Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, VIC Australia ,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, NSW Australia ,grid.62560.370000 0004 0378 8294Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA USA ,grid.38142.3c000000041936754XDivision of Sleep Medicine, Harvard Medical School, Boston, MA USA
| | - Andrew J. K. Phillips
- grid.1002.30000 0004 1936 7857Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, 18 Innovation Walk, Clayton, VIC 3800 Australia ,Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, VIC Australia
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18
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Booker LA, Barnes M, Alvaro P, Collins A, Chai-Coetzer CL, McMahon M, Lockley SW, Rajaratnam SMW, Howard ME, Sletten TL. The role of sleep hygiene in the risk of Shift Work Disorder in nurses. Sleep 2021; 43:5602177. [PMID: 31637435 DOI: 10.1093/sleep/zsz228] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 08/21/2019] [Indexed: 12/27/2022] Open
Abstract
A high proportion (20%-30%) of shift workers experience Shift Work Disorder (SWD), characterized by chronic sleepiness and/or insomnia associated with work schedules. The reasons for individual variation in shift work tolerance are not well understood, however. The aim of this study was to identify individual factors that contribute to the risk of SWD. Nurses (n = 202) were categorized as low or high risk of SWD based on the Shift Work Disorder Questionnaire. Participants provided demographic and lifestyle information and completed the Sleep Hygiene Index (SHI) and Morningness-Eveningness Questionnaire (MEQ). High risk of SWD was associated with poorer sleep hygiene (SHI, 35.41 ± 6.19 vs. 31.49 ± 7.08, p < .0001) and greater eveningness (MEQ, 34.73 ± 6.13 vs. 37.49 ± 6.45, p = .005) compared to low risk. No other factors, including body mass index, marital status, having children, or caffeine or alcohol intake were significant. Logistic regression showed that SHI was the most significant contributing factor to SWD risk (odds ratio [OR] = 1.09, 95% confidence interval [CI] = 1.04 to 1.14). Standardized odds ratio further revealed that with every unit increase on the SHI score, the odds of being at high risk of SWD increased by 80% (OR = 1.84). Most individuals at high risk of SWD reported "always" or "frequently" going to bed at different times (79%) and waking at different times (83%; compared to 58%, p = .017, and 61%, p = .002, respectively for the low-risk group), as well as going to bed stressed/angry (67% vs. 41%, p < .0001) and/or planning/worrying in bed (54% vs. 22%, p < .0001). Interventions aimed at improving sleep hygiene practices and psychological health of shift workers may help reduce the risk of SWD.
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Affiliation(s)
- Lauren A Booker
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia.,Department of Medicine, Cooperative Research Centre for Alertness, Safety and Productivity, University of Melbourne, Melbourne, Victoria, Australia.,Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Maree Barnes
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Pasquale Alvaro
- Flinders University, School of Psychology, Adelaide, South Australia, Australia
| | - Allison Collins
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Ching Li Chai-Coetzer
- Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Flinders University, Adelaide, South Australia, Australia.,Respiratory and Sleep Services, Southern Adelaide Local Health Network, SA Health, Adelaide, South Australia, Australia
| | - Marcus McMahon
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Steven W Lockley
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia.,Department of Medicine, Cooperative Research Centre for Alertness, Safety and Productivity, University of Melbourne, Melbourne, Victoria, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA
| | - Shantha M W Rajaratnam
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia.,Department of Medicine, Cooperative Research Centre for Alertness, Safety and Productivity, University of Melbourne, Melbourne, Victoria, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA
| | - Mark E Howard
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia.,Department of Medicine, Cooperative Research Centre for Alertness, Safety and Productivity, University of Melbourne, Melbourne, Victoria, Australia.,Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Tracey L Sletten
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia.,Department of Medicine, Cooperative Research Centre for Alertness, Safety and Productivity, University of Melbourne, Melbourne, Victoria, Australia
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19
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Sletten TL, Raman B, Magee M, Ferguson SA, Kennaway DJ, Grunstein RR, Lockley SW, Rajaratnam SMW. A Blue-Enriched, Increased Intensity Light Intervention to Improve Alertness and Performance in Rotating Night Shift Workers in an Operational Setting. Nat Sci Sleep 2021; 13:647-657. [PMID: 34079409 PMCID: PMC8163632 DOI: 10.2147/nss.s287097] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 02/04/2021] [Indexed: 12/20/2022] Open
Abstract
PURPOSE This study examined the efficacy of a lighting intervention that increased both light intensity and short-wavelength (blue) light content to improve alertness, performance and mood in night shift workers in a chemical plant. PATIENTS AND METHODS During rostered night shifts, 28 workers (46.0±10.8 years; 27 male) were exposed to two light conditions each for two consecutive nights (~19:00-07:00 h) in a counterbalanced repeated measures design: traditional-spectrum lighting set at pre-study levels (43 lux, 4000 K) versus higher intensity, blue-enriched lighting (106 lux, 17,000 K), equating to a 4.5-fold increase in melanopic illuminance (24 to 108 melanopic illuminance). Participants completed the Karolinska Sleepiness Scale, subjective mood ratings, and the Psychomotor Vigilance Task (PVT) every 2-4 hours during the night shift. RESULTS A significant main effect of time indicated KSS, PVT mean reaction time, number of PVT lapses (reaction times > 500 ms) and subjective tension, misery and depression worsened over the course of the night shift (p<0.05). Percentage changes in KSS (p<0.05, partial η2=0.14) and PVT mean reaction time (p<0.05, partial η2=0.19) and lapses (p<0.05, partial η2=0.17) in the middle and end of night shift, expressed relative to start of shift, were significantly improved during the lighting intervention compared to the traditional lighting condition. Self-reported mood did not significantly differ between conditions (p>0.05). CONCLUSION Our findings, showing improvements in alertness and performance with exposure to blue-enriched, increased intensity light, provide support for light to be used as a countermeasure for impaired alertness in night shift work settings.
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Affiliation(s)
- Tracey L Sletten
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Bhairavi Raman
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Michelle Magee
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Sally A Ferguson
- Central Queensland University, Appleton Institute, Goodwood, SA, Australia
| | - David J Kennaway
- Robinson Research Institute, School of Medicine, Discipline of Obstetrics and Gynaecology, University of Adelaide, Adelaide, SA, Australia
| | - Ronald R Grunstein
- Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia.,Department of Respiratory & Sleep Medicine, Royal Prince Alfred Hospital, Sydney, NSW, Australia
| | - Steven W Lockley
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Shantha M W Rajaratnam
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
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20
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Magee M, Sletten TL, Murray JM, Gordon CJ, Lovato N, Bartlett DJ, Kennaway DJ, Lockley SW, Lack LC, Grunstein RR, Archer SN, Rajaratnam SMW. A PERIOD3 variable number tandem repeat polymorphism modulates melatonin treatment response in delayed sleep-wake phase disorder. J Pineal Res 2020; 69:e12684. [PMID: 32682347 DOI: 10.1111/jpi.12684] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 06/09/2020] [Accepted: 07/09/2020] [Indexed: 12/15/2022]
Abstract
We examined whether a polymorphism of the PERIOD3 gene (PER3; rs57875989) modulated the sleep-promoting effects of melatonin in Delayed Sleep-Wake Phase Disorder (DSWPD). One hundred and four individuals (53 males; 29.4 ±10.0 years) with DSWPD and a delayed dim light melatonin onset (DLMO) collected buccal swabs for genotyping (PER34/4 n = 43; PER3 5 allele [heterozygous and homozygous] n = 60). Participants were randomised to placebo or 0.5 mg melatonin taken 1 hour before desired bedtime (or ~1.45 hours before DLMO), with sleep attempted at desired bedtime (4 weeks; 5-7 nights/week). We assessed sleep (diary and actigraphy), Pittsburgh Sleep Quality Index (PSQI), Insomnia Severity Index (ISI), Patient-Reported Outcomes Measurement Information System (PROMIS: Sleep Disturbance, Sleep-Related Impairment), Sheehan Disability Scale (SDS) and Patient- and Clinician-Global Improvement (PGI-C, CGI-C). Melatonin treatment response on actigraphic sleep onset time did not differ between genotypes. For PER34/4 carriers, self-reported sleep onset time was advanced by a larger amount and sleep onset latency (SOL) was shorter in melatonin-treated patients compared to those receiving placebo (P = .008), while actigraphic sleep efficiency in the first third of the sleep episode (SE T1) did not differ. For PER3 5 carriers, actigraphic SOL and SE T1 showed a larger improvement with melatonin (P < .001). Melatonin improved ISI (P = .005), PROMIS sleep disturbance (P < .001) and sleep-related impairment (P = .017), SDS (P = .019), PGI-C (P = .028) and CGI-C (P = .016) in PER34/4 individuals only. Melatonin did not advance circadian phase. Overall, PER34/4 DSWPD patients have a greater response to melatonin treatment. PER3 genotyping may therefore improve DSWPD patient outcomes.
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Affiliation(s)
- Michelle Magee
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia
- Centre for Neuroscience of Speech, Department of Audiology and Speech Pathology, University of Melbourne, Parkville, Victoria, Australia
| | - Tracey L Sletten
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia
| | - Jade M Murray
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia
| | - Christopher J Gordon
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia
- Woolcock Institute of Medical Research, Sydney, NSW, Australia
- Sydney Nursing School, The University of Sydney, Sydney, NSW, Australia
| | - Nicole Lovato
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia
- Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, School of Medicine, Flinders University, Adelaide, South Australia, Australia
| | - Delwyn J Bartlett
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia
- Woolcock Institute of Medical Research, Sydney, NSW, Australia
| | - David J Kennaway
- Robinson Research Institute, Adelaide School of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Steven W Lockley
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Leon C Lack
- Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, School of Medicine, Flinders University, Adelaide, South Australia, Australia
| | - Ronald R Grunstein
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia
- Woolcock Institute of Medical Research, Sydney, NSW, Australia
| | - Simon N Archer
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - Shantha M W Rajaratnam
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
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21
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Stone JE, Postnova S, Sletten TL, Rajaratnam SM, Phillips AJ. Computational approaches for individual circadian phase prediction in field settings. ACTA ACUST UNITED AC 2020. [DOI: 10.1016/j.coisb.2020.07.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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22
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Mulhall MD, Cori J, Sletten TL, Kuo J, Lenné MG, Magee M, Spina MA, Collins A, Anderson C, Rajaratnam SMW, Howard ME. A pre-drive ocular assessment predicts alertness and driving impairment: A naturalistic driving study in shift workers. Accid Anal Prev 2020; 135:105386. [PMID: 31805427 DOI: 10.1016/j.aap.2019.105386] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 09/19/2019] [Accepted: 11/24/2019] [Indexed: 06/10/2023]
Abstract
Sleepiness is a major contributor to motor vehicle crashes and shift workers are particularly vulnerable. There is currently no validated objective field-based measure of sleep-related impairment prior to driving. Ocular parameters are promising markers of continuous driver alertness in laboratory and track studies, however their ability to determine fitness-to-drive in naturalistic driving is unknown. This study assessed the efficacy of a pre-drive ocular assessment for predicting sleep-related impairment in naturalistic driving, in rotating shift workers. Fifteen healthcare workers drove an instrumented vehicle for 2 weeks, while working a combination of day, evening and night shifts. The vehicle monitored lane departures and behavioural microsleeps (blinks >500 ms) during the drive. Immediately prior to driving, ocular parameters were assessed with a 4-min test. Lane departures and behavioural microsleeps occurred on 17.5 % and 10 % of drives that had pre-drive assessments, respectively. Pre-drive blink duration significantly predicted behavioural microsleeps and showed promise for predicting lane departures (AUC = 0.79 and 0.74). Pre-drive percentage of time with eyes closed had high accuracy for predicting lane departures and behavioural microsleeps (AUC = 0.73 and 0.96), although was not statistically significant. Pre-drive psychomotor vigilance task variables were not statistically significant predictors of lane departures. Self-reported sleep-related and hazardous driving events were significantly predicted by mean blink duration (AUC = 0.65 and 0.69). Measurement of ocular parameters pre-drive predict drowsy driving during naturalistic driving, demonstrating potential for fitness-to-drive assessment in operational environments.
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Affiliation(s)
- Megan D Mulhall
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Melbourne, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia
| | - Jennifer Cori
- Institute for Breathing and Sleep, Austin Health, Victoria, Australia
| | - Tracey L Sletten
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Melbourne, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia
| | - Jonny Kuo
- Seeing Machines Ltd., 80 Mildura St., Fyshwick, ACT, Australia; Monash University Accident Research Centre, Monash University, Victoria, Australia
| | - Michael G Lenné
- Seeing Machines Ltd., 80 Mildura St., Fyshwick, ACT, Australia; Monash University Accident Research Centre, Monash University, Victoria, Australia
| | - Michelle Magee
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Melbourne, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia
| | - Marie-Antoinette Spina
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Melbourne, Victoria, Australia
| | - Allison Collins
- Institute for Breathing and Sleep, Austin Health, Victoria, Australia
| | - Clare Anderson
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Melbourne, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia
| | - Shantha M W Rajaratnam
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Melbourne, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia
| | - Mark E Howard
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Melbourne, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia; Institute for Breathing and Sleep, Austin Health, Victoria, Australia.
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23
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Affiliation(s)
- Tracey L Sletten
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Australia
| | | | - Alec J Davidson
- Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA
| | - Eve Van Cauter
- Department of Medicine, University of Chicago, Chicago, IL
| | - Shantha M W Rajaratnam
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Australia.,Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Boston, MA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA
| | - Frank A J L Scheer
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Boston, MA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA
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24
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Stone JE, Phillips AJK, Ftouni S, Magee M, Howard M, Lockley SW, Sletten TL, Anderson C, Rajaratnam SMW, Postnova S. Generalizability of A Neural Network Model for Circadian Phase Prediction in Real-World Conditions. Sci Rep 2019; 9:11001. [PMID: 31358781 PMCID: PMC6662750 DOI: 10.1038/s41598-019-47311-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 06/04/2019] [Indexed: 01/24/2023] Open
Abstract
A neural network model was previously developed to predict melatonin rhythms accurately from blue light and skin temperature recordings in individuals on a fixed sleep schedule. This study aimed to test the generalizability of the model to other sleep schedules, including rotating shift work. Ambulatory wrist blue light irradiance and skin temperature data were collected in 16 healthy individuals on fixed and habitual sleep schedules, and 28 rotating shift workers. Artificial neural network models were trained to predict the circadian rhythm of (i) salivary melatonin on a fixed sleep schedule; (ii) urinary aMT6s on both fixed and habitual sleep schedules, including shift workers on a diurnal schedule; and (iii) urinary aMT6s in rotating shift workers on a night shift schedule. To determine predicted circadian phase, center of gravity of the fitted bimodal skewed baseline cosine curve was used for melatonin, and acrophase of the cosine curve for aMT6s. On a fixed sleep schedule, the model predicted melatonin phase to within ± 1 hour in 67% and ± 1.5 hours in 100% of participants, with mean absolute error of 41 ± 32 minutes. On diurnal schedules, including shift workers, the model predicted aMT6s acrophase to within ± 1 hour in 66% and ± 2 hours in 87% of participants, with mean absolute error of 63 ± 67 minutes. On night shift schedules, the model predicted aMT6s acrophase to within ± 1 hour in 42% and ± 2 hours in 53% of participants, with mean absolute error of 143 ± 155 minutes. Prediction accuracy was similar when using either 1 (wrist) or 11 skin temperature sensor inputs. These findings demonstrate that the model can predict circadian timing to within ± 2 hours for the vast majority of individuals on diurnal schedules, using blue light and a single temperature sensor. However, this approach did not generalize to night shift conditions.
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Affiliation(s)
- Julia E Stone
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia.
| | - Andrew J K Phillips
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Suzanne Ftouni
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Michelle Magee
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Mark Howard
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia
- Institute for Breathing and Sleep, Austin Health, Victoria, Australia
| | - Steven W Lockley
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Tracey L Sletten
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Clare Anderson
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Shantha M W Rajaratnam
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Svetlana Postnova
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
- School of Physics, University of Sydney, Sydney, New South Wales, Australia
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25
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Booker LA, Sletten TL, Alvaro PK, Barnes M, Collins A, Chai-Coetzer CL, Naqvi A, McMahon M, Lockley SW, Rajaratnam SMW, Howard ME. Exploring the associations between shift work disorder, depression, anxiety and sick leave taken amongst nurses. J Sleep Res 2019; 29:e12872. [PMID: 31144389 DOI: 10.1111/jsr.12872] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 03/28/2019] [Accepted: 04/21/2019] [Indexed: 11/26/2022]
Abstract
This study aimed to evaluate the association between shift work disorder and mental health in hospital-based nurses. Staff completed an online survey comprising demographic questions, the Shift Work Disorder Questionnaire, Patient Health-9 and the General Anxiety Disorder-7 scale. Sick leave data were collected from archival records from the Human Resources Department. Two hundred and two nurses (95% female; age M = 35.28 years ± SD = 12) participated (42% of eligible staff). Those at high risk of shift work disorder had higher depression (M = 7.54 ± SD = 4.28 vs. M = 3.78 ± SD = 3.24; p < 0.001) and anxiety (M = 5.66 ± SD = 3.82 vs. M = 2.83 ± SD = 3.33, p < 0.001) compared to those at low risk. Linear regression models showed that being at high risk of shift work disorder was the most significant predictor of depression, explaining 18.8% of the variance in depression (R2 = 0.188, adjusted R2 = 0.184, F(1, 200) = 46.20, p < 0.001). Shift work disorder combined with the number of night shifts and alcoholic drinks on non-work days accounted for 49.7% of the variance in anxiety scores (R2 = 0.497, adjusted R2 = 0.453, F(3, 35) = 11.51, p < 0.001). Mean sick leave in those with high risk of shift work disorder was 136.17 hr (SD = 113.11) versus 103.98 hr (SD = 94.46) in others (p = 0.057). Depression and years of shift work accounted for 18.9% of the variance in sick leave taken (R2 = 0.189, adjusted R2 = 0.180, F(2, 175) = 20.36, p < 0.001). Shift work disorder is strongly associated with depression and anxiety, providing a potential target to improve mental health in shift workers. Depression, in turn, is a significant contributing factor to sick leave.
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Affiliation(s)
- Lauren A Booker
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia
| | - Tracey L Sletten
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia
| | - Pasquale K Alvaro
- School of Psychology, Flinders University, Adelaide, South Australia, Australia
| | - Maree Barnes
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,University of Melbourne, Parkville, Victoria, Australia
| | - Allison Collins
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Ching Li Chai-Coetzer
- Adelaide Institute for Sleep Health: A Flinders Centre of Research Excellence, Flinders University, Adelaide, South Australia, Australia.,Respiratory and Sleep Services, Southern Adelaide Local Health Network, SA Health, Adelaide, South Australia, Australia
| | - Aqsa Naqvi
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Marcus McMahon
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Steven W Lockley
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts.,Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts
| | - Shantha M W Rajaratnam
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts.,Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts
| | - Mark E Howard
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Australia.,University of Melbourne, Parkville, Victoria, Australia
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26
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Mulhall MD, Sletten TL, Magee M, Stone JE, Ganesan S, Collins A, Anderson C, Lockley SW, Howard ME, Rajaratnam SMW. Sleepiness and driving events in shift workers: the impact of circadian and homeostatic factors. Sleep 2019; 42:5382317. [DOI: 10.1093/sleep/zsz074] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 02/03/2019] [Indexed: 11/12/2022] Open
Affiliation(s)
- Megan D Mulhall
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria Australia
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Tracey L Sletten
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria Australia
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Michelle Magee
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria Australia
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Julia E Stone
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria Australia
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Saranea Ganesan
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria Australia
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Allison Collins
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria Australia
- Institute for Breathing and Sleep, Austin Health, Melbourne, Victoria, Australia
| | - Clare Anderson
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria Australia
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
| | - Steven W Lockley
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria Australia
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA
| | - Mark E Howard
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria Australia
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
- Institute for Breathing and Sleep, Austin Health, Melbourne, Victoria, Australia
| | - Shantha M W Rajaratnam
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria Australia
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA
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27
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Ganesan S, Magee M, Stone JE, Mulhall MD, Collins A, Howard ME, Lockley SW, Rajaratnam SMW, Sletten TL. The Impact of Shift Work on Sleep, Alertness and Performance in Healthcare Workers. Sci Rep 2019; 9:4635. [PMID: 30874565 PMCID: PMC6420632 DOI: 10.1038/s41598-019-40914-x] [Citation(s) in RCA: 141] [Impact Index Per Article: 28.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 02/19/2019] [Indexed: 01/19/2023] Open
Abstract
Shift work is associated with impaired alertness and performance due to sleep loss and circadian misalignment. This study examined sleep between shift types (day, evening, night), and alertness and performance during day and night shifts in 52 intensive care workers. Sleep and wake duration between shifts were evaluated using wrist actigraphs and diaries. Subjective sleepiness (Karolinska Sleepiness Scale, KSS) and Psychomotor Vigilance Test (PVT) performance were examined during day shift, and on the first and subsequent night shifts (3rd, 4th or 5th). Circadian phase was assessed using urinary 6-sulphatoxymelatonin rhythms. Sleep was most restricted between consecutive night shifts (5.74 ± 1.30 h), consecutive day shifts (5.83 ± 0.92 h) and between evening and day shifts (5.20 ± 0.90 h). KSS and PVT mean reaction times were higher at the end of the first and subsequent night shift compared to day shift, with KSS highest at the end of the first night. On nights, working during the circadian acrophase of the urinary melatonin rhythm led to poorer outcomes on the KSS and PVT. In rotating shift workers, early day shifts can be associated with similar sleep restriction to night shifts, particularly when scheduled immediately following an evening shift. Alertness and performance remain most impaired during night shifts given the lack of circadian adaptation to night work. Although healthcare workers perceive themselves to be less alert on the first night shift compared to subsequent night shifts, objective performance is equally impaired on subsequent nights.
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Affiliation(s)
- Saranea Ganesan
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Michelle Magee
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Julia E Stone
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Megan D Mulhall
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Allison Collins
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Mark E Howard
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.,Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Steven W Lockley
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.,Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Shantha M W Rajaratnam
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.,Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Tracey L Sletten
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia. .,Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.
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28
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Bonham MP, Kaias E, Zimberg I, Leung GKW, Davis R, Sletten TL, Windsor-Aubrey H, Huggins CE. Effect of Night Time Eating on Postprandial Triglyceride Metabolism in Healthy Adults: A Systematic Literature Review. J Biol Rhythms 2019; 34:119-130. [DOI: 10.1177/0748730418824214] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Eating at night time, as is frequent in shift workers, may contribute to increased cardiovascular disease (CVD) risk through a disruption in usual lipid metabolism, resulting in repeated and sustained hyperlipidemia at night. This systematic review aimed to investigate the impact of eating a meal at night compared with the same meal eaten during the day on postprandial lipemia. Six databases were searched: CINAHL Plus, Cochrane Library, EMBASE, Ovid MEDLINE, Informit, and SCOPUS. Eligible studies were original research cross-over design with a minimum fasting period of 5 h before testing preceded by a standardized control meal; measured postprandial triacylglycerol (TAG) for 5 h or greater; had meal time between 0700 h and 1600 h for day time and between 2000 h and 0400 h for night time; and had within-study test meals (food or drink) that were identical in macronutrient composition and energy. Two authors independently completed eligibility and quality assessment using the American Dietetic Association Quality Criteria Checklist for Primary Research. After removing duplicates, 4,423 articles were screened, yielding 5 studies for qualitative synthesis. All studies identified at least one parameter of the postprandial TAG response that was different as a result of meal time (e.g., the total concentration or the time course kinetics). Two studies reported a greater total TAG concentration (area under curve) at night compared with day, and 3 studies found no difference. Four studies reported that the kinetics of the postprandial time course of TAGs was different at night compared with during the day. Inconsistent reporting in the primary studies was a limitation of the review. Night eating may negatively affect postprandial lipemia and this review shows there is a need to rigorously test this using standardized methods and analysis with larger sample sizes. This is critical for informing strategies to lower CVD risk for shift workers.
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Affiliation(s)
- Maxine P. Bonham
- Department of Nutrition, Dietetics and Food, Monash University, VIC Australia
| | - Elleni Kaias
- Department of Nutrition, Dietetics and Food, Monash University, VIC Australia
| | - Iona Zimberg
- Department of Nutrition, Dietetics and Food, Monash University, VIC Australia
| | - Gloria K. W. Leung
- Department of Nutrition, Dietetics and Food, Monash University, VIC Australia
| | - Rochelle Davis
- Department of Nutrition, Dietetics and Food, Monash University, VIC Australia
| | - Tracey L. Sletten
- Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, VIC, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, VIC, Australia
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29
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Booker LA, Magee M, Rajaratnam SMW, Sletten TL, Howard ME. Individual vulnerability to insomnia, excessive sleepiness and shift work disorder amongst healthcare shift workers. A systematic review. Sleep Med Rev 2018; 41:220-233. [PMID: 29680177 DOI: 10.1016/j.smrv.2018.03.005] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 03/16/2018] [Accepted: 03/21/2018] [Indexed: 12/21/2022]
Abstract
Shift workers often experience reduced sleep quality, duration and/or excessive sleepiness due to the imposed conflict between work and their circadian system. About 20-30% of shift workers experience prominent insomnia symptoms and excessive daytime sleepiness consistent with the circadian rhythm sleep disorder known as shift work disorder. Individual factors may influence this vulnerability to shift work disorder or sleep-related impairment associated with shift work. This paper was registered with Prospero and was conducted using recommended standards for systematic reviews and meta-analyses. Published literature that measured sleep-related impairment associated with shift work including reduced sleep quality and duration and increased daytime sleepiness amongst healthcare shift workers and explored characteristics associated with individual variability were reviewed. Fifty-eight studies were included. Older age, morning-type, circadian flexibility, being married or having children, increased caffeine intake, higher scores on neuroticism and lower on hardiness were related to a higher risk of sleep-related impairment in response to shift work, whereas physical activity was a protective factor. The review highlights the diverse range of measurement tools used to evaluate the impact of shift work on sleep. Use of standardised and validated tools would enable cross-study comparisons. Longitudinal studies are required to establish causal relationships between individual factors and the development of shift work disorder.
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Affiliation(s)
- Lauren A Booker
- Institute for Breathing and Sleep, Austin Health, Austin Hospital, Heidelberg, Victoria, Australia; School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.
| | - Michelle Magee
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
| | - Shantha M W Rajaratnam
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
| | - Tracey L Sletten
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia
| | - Mark E Howard
- Institute for Breathing and Sleep, Austin Health, Austin Hospital, Heidelberg, Victoria, Australia; School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, Australia; Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia; Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
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30
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McGlashan EM, Burns AC, Murray JM, Sletten TL, Magee M, Rajaratnam SMW, Cain SW. The pupillary light reflex distinguishes between circadian and non-circadian delayed sleep phase disorder (DSPD) phenotypes in young adults. PLoS One 2018; 13:e0204621. [PMID: 30261080 PMCID: PMC6160141 DOI: 10.1371/journal.pone.0204621] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 09/11/2018] [Indexed: 11/19/2022] Open
Abstract
This study investigated the utility of the pupillary light reflex as a method of differentiating DSPD patients with delayed melatonin timing relative to desired/required sleep time (circadian type) and those with non-delayed melatonin timing (non-circadian type). All participants were young adults, with a total of 14 circadian DSPD patients (M = 28.14, SD = 5.26), 12 non-circadian DSPD patients (M = 29.42, SD = 11.51) and 51 healthy controls (M = 21.47 SD = 3.16) completing the protocol. All participants were free of central nervous system acting medications and abstained from caffeine and alcohol on the day of the assessment. Two pupillary light reflex measurements were completed by each participant, one with a 1s dim (~10 lux) light exposure, and one with a 1s bright (~1500 lux) light exposure. Circadian DSPD patients showed a significantly faster pupillary light reflex than both non-circadian DSPD patients and healthy controls. Non-circadian patients and healthy controls did not differ significantly. Receiver operating characteristic curves were generated to determine the utility of mean and maximum constriction velocity in differentiating the two DSPD phenotypes, and these demonstrated high levels of sensitivity (69.23–-100%) and specificity (66.67–91.67%) at their optimal cut offs. The strongest predictor of DSPD phenotype was the mean constriction velocity to bright light (AUC = 0.87). These results support the potential for the pupillary light reflex to clinically differentiate between DSPD patients with normal vs. delayed circadian timing relative to desired bedtime, without the need for costly and time-consuming circadian assessments.
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Affiliation(s)
- Elise M. McGlashan
- Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Melbourne, Australia
| | - Angus C. Burns
- Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Melbourne, Australia
| | - Jade M. Murray
- Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Melbourne, Australia
| | - Tracey L. Sletten
- Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Melbourne, Australia
| | - Michelle Magee
- Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Melbourne, Australia
| | - Shantha M. W. Rajaratnam
- Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Melbourne, Australia
| | - Sean W. Cain
- Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Melbourne, Australia
- * E-mail:
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31
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Porcheret K, Wald L, Fritschi L, Gerkema M, Gordijn M, Merrrow M, Rajaratnam SMW, Rock D, Sletten TL, Warman G, Wulff K, Roenneberg T, Foster RG. Chronotype and environmental light exposure in a student population. Chronobiol Int 2018; 35:1365-1374. [PMID: 29913073 PMCID: PMC6234547 DOI: 10.1080/07420528.2018.1482556] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In humans and most other species, changes in the intensity and duration of light provide a critical set of signals for the synchronisation of the circadian system to the astronomical day. The timing of activity within the 24 h day defines an individual's chronotype, i.e. morning, intermediate or evening type. The aim of this study was to investigate the associations between environmental light exposure, due to geographical location, on the chronotype of university students. Over 6 000 university students from cities in the Northern Hemisphere (Oxford, Munich and Groningen) and Southern Hemisphere (Perth, Melbourne and Auckland) completed the Munich ChronoType Questionnaire. In parallel, light measures (daily irradiance, timing of sunrise and sunset) were compiled from satellite or ground stations at each of these locations. Our data shows that later mid-sleep point on free days (corrected for oversleep on weekends MFSsc) is associated with (i) residing further from the equator, (ii) a later sunset, (iii) spending more time outside and (iv) waking from sleep significantly after sunrise. However, surprisingly, MSFsc did not correlate with daily light intensity at the different geographical locations. Although these findings appear to contradict earlier studies suggesting that in the wider population increased light exposure is associated with an earlier chronotype, our findings are derived exclusively from a student population aged between 17 and 26 years. We therefore suggest that the age and occupation of our population increase the likelihood that these individuals will experience relatively little light exposure in the morning whilst encountering more light exposure later in the day, when light has a delaying effect upon the circadian system.
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Affiliation(s)
- Kate Porcheret
- a Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences , University of Oxford , Oxford , UK
| | - Lucien Wald
- b Centre for Observation, Impacts, Energy , MINES ParisTech, PSL Research University , Paris , France
| | - Lin Fritschi
- c School of Public Health , Curtin University , Perth , Australia
| | - Menno Gerkema
- d Chronobiology unit, Groningen Institute for Evolutionary Life Sciences , University of Groningen , Groningen , The Netherlands
| | - Marijke Gordijn
- d Chronobiology unit, Groningen Institute for Evolutionary Life Sciences , University of Groningen , Groningen , The Netherlands.,e Chrono@Work , Groningen , The Netherlands
| | - Martha Merrrow
- f Molecular Chronobiology , Institute of Medical Psychology, LMU Munich , Munich , Germany
| | - Shantha M W Rajaratnam
- g Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences , Monash University , Melbourne , Australia
| | - Daniel Rock
- h WA Primary Health Alliance , Perth , Australia.,i School of Psychiatry and Clinical Neurosciences , The University of Western Australia , Perth , Australia
| | - Tracey L Sletten
- g Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences , Monash University , Melbourne , Australia
| | - Guy Warman
- j Chronobiology Group, Department of Anaesthesiology, School of Medicine, Faculty of Medical and Health Sciences , University of Auckland , Auckland , New Zealand
| | - Katharina Wulff
- a Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences , University of Oxford , Oxford , UK
| | - Till Roenneberg
- f Molecular Chronobiology , Institute of Medical Psychology, LMU Munich , Munich , Germany
| | - Russell G Foster
- a Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences , University of Oxford , Oxford , UK
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Sletten TL, Magee M, Murray JM, Gordon CJ, Lovato N, Kennaway DJ, Gwini SM, Bartlett DJ, Lockley SW, Lack LC, Grunstein RR, Rajaratnam SMW. Efficacy of melatonin with behavioural sleep-wake scheduling for delayed sleep-wake phase disorder: A double-blind, randomised clinical trial. PLoS Med 2018; 15:e1002587. [PMID: 29912983 PMCID: PMC6005466 DOI: 10.1371/journal.pmed.1002587] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 05/15/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Delayed Sleep-Wake Phase Disorder (DSWPD) is characterised by sleep initiation insomnia when attempting sleep at conventional times and difficulty waking at the required time for daytime commitments. Although there are published therapeutic guidelines for the administration of melatonin for DSWPD, to our knowledge, randomised controlled trials are lacking. This trial tested the efficacy of 0.5 mg melatonin, combined with behavioural sleep-wake scheduling, for improving sleep initiation in clinically diagnosed DSWPD patients with a delayed endogenous melatonin rhythm relative to patient-desired (or -required) bedtime (DBT). METHODS This randomised, placebo-controlled, double-blind clinical trial was conducted in an Australian outpatient DSWPD population. Following 1-wk baseline, clinically diagnosed DSWPD patients with delayed melatonin rhythm relative to DBT (salivary dim light melatonin onset [DLMO] after or within 30 min before DBT) were randomised to 4-wk treatment with 0.5 mg fast-release melatonin or placebo 1 h before DBT for at least 5 consecutive nights per week. All patients received behavioural sleep-wake scheduling, consisting of bedtime scheduled at DBT. The primary outcome was actigraphic sleep onset time. Secondary outcomes were sleep efficiency in the first third of time in bed (SE T1) on treatment nights, subjective sleep-related daytime impairment (Patient Reported Outcomes Measurement Information System [PROMIS]), PROMIS sleep disturbance, measures of daytime sleepiness, clinician-rated change in illness severity, and DLMO time. FINDINGS Between September 13, 2012 and September 1, 2014, 307 participants were registered; 116 were randomised to treatment (intention-to-treat n = 116; n = 62 males; mean age, 29.0 y). Relative to baseline and compared to placebo, sleep onset occurred 34 min earlier (95% confidence interval [CI] -60 to -8) in the melatonin group. SE T1 increased; PROMIS sleep-related impairment, PROMIS sleep disturbance, insomnia severity, and functional disability decreased; and a greater proportion of patients showed more than minimal clinician-rated improvement following melatonin treatment (52.8%) compared to placebo (24.0%) (P < 0.05). The groups did not differ in the number of nights treatment was taken per protocol. Post-treatment DLMO assessed in a subset of patients (n = 43) was not significantly different between groups. Adverse events included light-headedness, daytime sleepiness, and decreased libido, although rates were similar between treatment groups. The clinical benefits or safety of melatonin with long-term treatment were not assessed, and it remains unknown whether the same treatment regime would benefit patients experiencing DSWPD sleep symptomology without a delay in the endogenous melatonin rhythm. CONCLUSIONS In this study, melatonin treatment 1 h prior to DBT combined with behavioural sleep-wake scheduling was efficacious for improving objective and subjective measures of sleep disturbances and sleep-related impairments in DSWPD patients with delayed circadian phase relative to DBT. Improvements were achieved largely through the sleep-promoting effects of melatonin, combined with behavioural sleep-wake scheduling. TRIAL REGISTRATION This trial was registered with the Australian New Zealand Clinical Trials Registry, ACTRN12612000425897.
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Affiliation(s)
- Tracey L. Sletten
- Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, Victoria, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Victoria, Australia
| | - Michelle Magee
- Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, Victoria, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Victoria, Australia
| | - Jade M. Murray
- Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, Victoria, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Victoria, Australia
| | - Christopher J. Gordon
- Cooperative Research Centre for Alertness, Safety and Productivity, Victoria, Australia
- CIRUS, Woolcock Institute of Medical Research, University of Sydney, New South Wales, Australia
- Sydney Nursing School, University of Sydney, New South Wales, Australia
| | - Nicole Lovato
- Cooperative Research Centre for Alertness, Safety and Productivity, Victoria, Australia
- School of Psychology, Faculty of Social and Behavioural Sciences, Flinders University, South Australia, Australia
| | - David J. Kennaway
- Robinson Research Institute, School of Medicine, Discipline of Obstetrics and Gynaecology, University of Adelaide, Adelaide, South Australia, Australia
| | - Stella M. Gwini
- Department of Epidemiology and Preventative Medicine, Monash University, Victoria, Australia
- University Hospital Geelong, Barwon Health, Geelong, Victoria, Australia
| | - Delwyn J. Bartlett
- CIRUS, Woolcock Institute of Medical Research, University of Sydney, New South Wales, Australia
| | - Steven W. Lockley
- Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, Victoria, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Victoria, Australia
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Division of Sleep Medicine, Harvard Medical School, Massachusetts, United States of America
| | - Leon C. Lack
- School of Psychology, Faculty of Social and Behavioural Sciences, Flinders University, South Australia, Australia
| | - Ronald R. Grunstein
- Cooperative Research Centre for Alertness, Safety and Productivity, Victoria, Australia
- CIRUS, Woolcock Institute of Medical Research, University of Sydney, New South Wales, Australia
- Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, New South Wales, Australia
| | - Shantha M. W. Rajaratnam
- Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, Victoria, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Victoria, Australia
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Division of Sleep Medicine, Harvard Medical School, Massachusetts, United States of America
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Ganesan S, Magee M, Stone JE, Mulhall MD, Collins A, Howard M, Lockley SW, Rajaratnam S, Sletten TL. 0175 Shift Work and its Impact on Sleep, Alertness and Performance in Intensive Care Health Workers. Sleep 2018. [DOI: 10.1093/sleep/zsy061.174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- S Ganesan
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, AUSTRALIA
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, AUSTRALIA
| | - M Magee
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, AUSTRALIA
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, AUSTRALIA
| | - J E Stone
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, AUSTRALIA
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, AUSTRALIA
| | - M D Mulhall
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, AUSTRALIA
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, AUSTRALIA
| | - A Collins
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, AUSTRALIA
| | - M Howard
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, AUSTRALIA
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, AUSTRALIA
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, AUSTRALIA
| | - S W Lockley
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, AUSTRALIA
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, AUSTRALIA
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women’s Hospital, Boston, MA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA
| | - S Rajaratnam
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, AUSTRALIA
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, AUSTRALIA
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women’s Hospital, Boston, MA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA
| | - T L Sletten
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, AUSTRALIA
- School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Melbourne, Victoria, AUSTRALIA
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Stone JE, Sletten TL, Magee M, Ganesan S, Mulhall MD, Collins A, Howard M, Lockley SW, Rajaratnam SMW. Temporal dynamics of circadian phase shifting response to consecutive night shifts in healthcare workers: role of light-dark exposure. J Physiol 2018; 596:2381-2395. [PMID: 29589871 DOI: 10.1113/jp275589] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 02/02/2018] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Shift work is highly prevalent and is associated with significant adverse health impacts. There is substantial inter-individual variability in the way the circadian clock responds to changing shift cycles. The mechanisms underlying this variability are not well understood. We tested the hypothesis that light-dark exposure is a significant contributor to this variability; when combined with diurnal preference, the relative timing of light exposure accounted for 71% of individual variability in circadian phase response to night shift work. These results will drive development of personalised approaches to manage circadian disruption among shift workers and other vulnerable populations to potentially reduce the increased risk of disease in these populations. ABSTRACT Night shift workers show highly variable rates of circadian adaptation. This study examined the relationship between light exposure patterns and the magnitude of circadian phase resetting in response to night shift work. In 21 participants (nursing and medical staff in an intensive care unit) circadian phase was measured using 6-sulphatoxymelatonin at baseline (day/evening shifts or days off) and after 3-4 consecutive night shifts. Daily light exposure was examined relative to individual circadian phase to quantify light intensity in the phase delay and phase advance portions of the light phase response curve (PRC). There was substantial inter-individual variability in the direction and magnitude of phase shift after three or four consecutive night shifts (mean phase delay -1:08 ± 1:31 h; range -3:43 h delay to +3:07 h phase advance). The relative difference in the distribution of light relative to the PRC combined with diurnal preference accounted for 71% of the variability in phase shift. Regression analysis incorporating these factors estimated phase shift to within ±60 min in 85% of participants. No participants met criteria for partial adaptation to night work after three or four consecutive night shifts. Our findings provide evidence that the phase resetting that does occur is based on individual light exposure patterns relative to an individual's baseline circadian phase. Thus, a 'one size fits all' approach to promoting adaptation to shift work using light therapy, implemented without knowledge of circadian phase, may not be efficacious for all individuals.
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Affiliation(s)
- Julia E Stone
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Tracey L Sletten
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Michelle Magee
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Saranea Ganesan
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Megan D Mulhall
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia
| | - Allison Collins
- Institute for Breathing and Sleep, Austin Health, Victoria, Australia
| | - Mark Howard
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia.,Institute for Breathing and Sleep, Austin Health, Victoria, Australia
| | - Steven W Lockley
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Shantha M W Rajaratnam
- Cooperative Research Centre for Alertness, Safety and Productivity, Melbourne, Victoria, Australia.,School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Faculty of Medicine, Nursing & Health Sciences, Monash University, Clayton, Victoria, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
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Bonham MP, Leung GKW, Davis R, Sletten TL, Murgia C, Young MJ, Eikelis N, Lambert EA, Huggins CE. Does modifying the timing of meal intake improve cardiovascular risk factors? Protocol of an Australian pilot intervention in night shift workers with abdominal obesity. BMJ Open 2018; 8:e020396. [PMID: 29540423 PMCID: PMC5857653 DOI: 10.1136/bmjopen-2017-020396] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
INTRODUCTION Shift work is an independent risk factor for cardiovascular disease (CVD). Shift workers who are awake overnight and sleep during the day are misaligned with their body's endogenous circadian rhythm. Eating at night contributes to this increased risk of CVD by forcing the body to actively break down and process nutrients at night. This pilot study aims to determine whether altering meal timing overnight, in a shift working population, will impact favourably on modifiable risk factors for CVD (postprandial bplasma lipids and glucose concentration). METHODS AND ANALYSIS A randomised cross-over study with two 4-week test periods, separated by a minimum of a 2-week washout will be undertaken. The effectiveness of redistributing energy intake overnight versus ad libitum eating patterns on CVD risk factors will be examined in night shift workers (n=20), using a standard acute test meal challenge protocol. Primary outcomes (postprandial lipids and glucose) will be compared between the two conditions: post-intervention and post-control period using analysis of variance. Potential effect size estimates to inform sample size calculations for a main trial will also be generated. ETHICS AND DISSEMINATION Ethics approval has been granted by the Monash University Human Research Ethics Committee (2017-8619-10329). Outcomes from this study will determine whether eliminating food intake for a defined period at night (1-6 am) impacts favourably on metabolic risk factors for CVD in night shift workers. Collective results from this novel trial will be disseminated through peer-reviewed journals, and national and international presentations. The results are essential to inform health promotion policies and guidelines for shift workers, especially those who aim to improve their metabolic health. TRIAL REGISTRATION NUMBER ACTRN12617000791336; Pre-results.
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Affiliation(s)
- Maxine P Bonham
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
| | - Gloria K W Leung
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
| | - Rochelle Davis
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
| | - Tracey L Sletten
- Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, Notting Hill, Victoria, Australia
- Cooperative Research Centre for Alertness, Safety and Productivity, Notting Hill, Victoria, Australia
| | - Chiara Murgia
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
| | - Morag J Young
- Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Nina Eikelis
- Iverson Health Innovation Research Institute, Swinburne University of Technology, Hawthorn, Victoria, Australia
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Elisabeth A Lambert
- Iverson Health Innovation Research Institute, Swinburne University of Technology, Hawthorn, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Australia
| | - Catherine E Huggins
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
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Grima NA, Rajaratnam SMW, Mansfield D, Sletten TL, Spitz G, Ponsford JL. Efficacy of melatonin for sleep disturbance following traumatic brain injury: a randomised controlled trial. BMC Med 2018; 16:8. [PMID: 29347988 PMCID: PMC5774131 DOI: 10.1186/s12916-017-0995-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 12/14/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The study aimed to determine the efficacy of melatonin supplementation for sleep disturbances in patients with traumatic brain injury (TBI). METHODS This is a randomised double-blind placebo-controlled two-period two-treatment (melatonin and placebo) crossover study. Outpatients were recruited from Epworth and Austin Hospitals Melbourne, Australia. They had mild to severe TBI (n = 33) reporting sleep disturbances post-injury (mean age 37 years, standard deviation 11 years; 67% men). They were given prolonged-release melatonin formulation (2 mg; Circadin®) and placebo capsules for 4 weeks each in a counterbalanced fashion separated by a 48-hour washout period. Treatment was taken nightly 2 hours before bedtime. Serious adverse events and side-effects were monitored. RESULTS Melatonin supplementation significantly reduced global Pittsburgh Sleep Quality Index scores relative to placebo, indicating improved sleep quality [melatonin 7.68 vs. placebo 9.47, original score units; difference -1.79; 95% confidence interval (CI), -2.70 to -0.88; p ≤ 0.0001]. Melatonin had no effect on sleep onset latency (melatonin 1.37 vs. placebo 1.42, log units; difference -0.05; 95% CI, -0.14 to 0.03; p = 0.23). With respect to the secondary outcomes, melatonin supplementation increased sleep efficiency on actigraphy, and vitality and mental health on the SF-36 v1 questionnaire (p ≤ 0.05 for each). Melatonin decreased anxiety on the Hospital Anxiety Depression Scale and fatigue on the Fatigue Severity Scale (p ≤ 0.05 for both), but had no significant effect on daytime sleepiness on the Epworth Sleepiness Scale (p = 0.15). No serious adverse events were reported. CONCLUSIONS Melatonin supplementation over a 4-week period is effective and safe in improving subjective sleep quality as well as some aspects of objective sleep quality in patients with TBI. TRIAL REGISTRATION Identifier: 12611000734965; Prospectively registered on 13 July 2011.
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Affiliation(s)
- Natalie A. Grima
- Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, 02215 MA USA
| | - Shantha M. W. Rajaratnam
- School of Psychological Sciences, Monash University, 18 Innovation Walk, Clayton Campus, Wellington Road, Melbourne, Victoria 3800 Australia
| | - Darren Mansfield
- Monash Lung and Sleep, Monash Health, 246 Clayton Road, Clayton, Victoria 3800 Australia
| | - Tracey L. Sletten
- School of Psychological Sciences, Monash University, 18 Innovation Walk, Clayton Campus, Wellington Road, Melbourne, Victoria 3800 Australia
| | - Gershon Spitz
- School of Psychological Sciences, Monash University, 18 Innovation Walk, Clayton Campus, Wellington Road, Melbourne, Victoria 3800 Australia
| | - Jennie L. Ponsford
- School of Psychological Sciences, Monash University, 18 Innovation Walk, Clayton Campus, Wellington Road, Melbourne, Victoria 3800 Australia
- Monash-Epworth Rehabilitation Research Centre, Epworth Healthcare, 89 Bridge Road, Richmond, 3121 Victoria Australia
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Boardman JM, Bei B, Mellor A, Anderson C, Sletten TL, Drummond SPA. The ability to self‐monitor cognitive performance during 60 h total sleep deprivation and following 2 nights recovery sleep. J Sleep Res 2017; 27:e12633. [DOI: 10.1111/jsr.12633] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 10/04/2017] [Indexed: 12/22/2022]
Affiliation(s)
- Johanna M. Boardman
- Monash Institute of Cognitive and Clinical Neurosciences School of Psychological Sciences Monash University Victoria Australia
| | - Bei Bei
- Monash Institute of Cognitive and Clinical Neurosciences School of Psychological Sciences Monash University Victoria Australia
| | - Alix Mellor
- Monash Institute of Cognitive and Clinical Neurosciences School of Psychological Sciences Monash University Victoria Australia
| | - Clare Anderson
- Monash Institute of Cognitive and Clinical Neurosciences School of Psychological Sciences Monash University Victoria Australia
| | - Tracey L. Sletten
- Monash Institute of Cognitive and Clinical Neurosciences School of Psychological Sciences Monash University Victoria Australia
| | - Sean P. A. Drummond
- Monash Institute of Cognitive and Clinical Neurosciences School of Psychological Sciences Monash University Victoria Australia
- Department of Psychiatry University of California San Diego CA USA
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Murray JM, Sletten TL, Magee M, Gordon C, Lovato N, Bartlett DJ, Kennaway DJ, Lack LC, Grunstein RR, Lockley SW, Rajaratnam SMW. Prevalence of Circadian Misalignment and Its Association With Depressive Symptoms in Delayed Sleep Phase Disorder. Sleep 2017; 40:2957267. [PMID: 28364473 DOI: 10.1093/sleep/zsw002] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2017] [Indexed: 11/14/2022] Open
Abstract
Study Objective To examine the prevalence of circadian misalignment in clinically diagnosed delayed sleep phase disorder (DSPD) and to compare mood and daytime functioning in those with and without a circadian basis for the disorder. Methods One hundred and eighty-two DSPD patients aged 16-64 years, engaged in regular employment or school, underwent sleep-wake monitoring in the home, followed by a sleep laboratory visit for assessment of salivary dim light melatonin onset (DLMO). Based on the DLMO assessments, patients were classified into two groups: circadian DSPD, defined as DLMO occurring at or after desired bedtime (DBT), or non-circadian DSPD, defined as DLMO occurring before DBT. Results One hundred and three patients (57%) were classified as circadian DSPD and 79 (43%) as non-circadian DSPD. DLMO occurred 1.66 hours later in circadian DSPD compared to non-circadian DSPD (p < .001). Moderate-severe depressive symptoms (Beck Depression Inventory-II) were more prevalent in circadian DSPD (14.0%) than in non-circadian DSPD (3.8%; p < .05). Relative to non-circadian DSPD patients, circadian DSPD patients had 4.31 times increased odds of at least mild depressive symptoms (95% CI 1.75 to 10.64; p < .01). No group differences were found for daytime sleepiness or function, but DSPD symptoms were rated by clinicians to be more severe in those with circadian DSPD. Conclusions Almost half of patients clinically diagnosed with DSPD did not show misalignment between the circadian pacemaker and the DBT, suggesting that the reported difficulties initiating sleep at the DBT are unlikely to be explained by the (mis)timing of the circadian rhythm of sleep propensity. Circadian misalignment in DSPD is associated with increased depressive symptoms and DSPD symptom severity.
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Affiliation(s)
- Jade M Murray
- Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia.,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, New South Wales, Australia
| | - Tracey L Sletten
- Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia.,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, New South Wales, Australia
| | - Michelle Magee
- Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia.,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, New South Wales, Australia
| | - Christopher Gordon
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia.,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, New South Wales, Australia.,Woolcock Institute of Medical Research and Sydney Local Health District, University of Sydney, Sydney, New South Wales, Australia.,Sydney Nursing School, University of Sydney, New South Wales, Australia
| | - Nicole Lovato
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia.,Adelaide Institute for Sleep Health, School of Medicine, Flinders University, Adelaide, South Australia
| | - Delwyn J Bartlett
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia.,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, New South Wales, Australia.,Woolcock Institute of Medical Research and Sydney Local Health District, University of Sydney, Sydney, New South Wales, Australia
| | - David J Kennaway
- Robinson Research Institute, School of Medicine, Discipline of Obstetrics and Gynaecology, University of Adelaide, Adelaide, South Australia, Australia
| | - Leon C Lack
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia.,Adelaide Institute for Sleep Health, School of Medicine, Flinders University, Adelaide, South Australia
| | - Ronald R Grunstein
- Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia.,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, New South Wales, Australia.,Woolcock Institute of Medical Research and Sydney Local Health District, University of Sydney, Sydney, New South Wales, Australia
| | - Steven W Lockley
- Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia.,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, New South Wales, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital; Division of Sleep Medicine, Harvard Medical School, Boston, MA; 9 Department of Medicine, Division of Sleep Medicine, Harvard Medical School, Boston, MA
| | - Shantha M W Rajaratnam
- Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.,Cooperative Research Centre for Alertness, Safety and Productivity, Clayton, Victoria, Australia.,NHMRC Centre for Sleep and Circadian Neurobiology, Sydney, New South Wales, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital; Division of Sleep Medicine, Harvard Medical School, Boston, MA; 9 Department of Medicine, Division of Sleep Medicine, Harvard Medical School, Boston, MA
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Sletten TL, Ftouni S, Nicholas CL, Magee M, Grunstein RR, Ferguson S, Kennaway DJ, O'Brien D, Lockley SW, Rajaratnam SMW. Randomised controlled trial of the efficacy of a blue-enriched light intervention to improve alertness and performance in night shift workers. Occup Environ Med 2017. [PMID: 28630378 DOI: 10.1136/oemed-2016-103818] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES Night workers often experience high levels of sleepiness due to misalignment of the sleep-wake cycle from the circadian pacemaker, in addition to acute and chronic sleep loss. Exposure to light, in particular short wavelength light, can improve alertness and neurobehavioural performance. This randomised controlled trial examined the efficacy of blue-enriched polychromatic light to improve alertness and neurobehavioural performance in night workers. DESIGN Participants were 71 night shift workers (42 males; 32.8±10.5 years) who worked at least 6 hours between 22:00 and 08:00 hours. Sleep-wake logs and wrist actigraphy were collected for 1-3 weeks, followed by 48-hour urine collection to measure the circadian 6-sulphatoxymelatonin (aMT6s) rhythm. On the night following at least two consecutive night shifts, workers attended a simulated night shift in the laboratory which included subjective and objective assessments of sleepiness and performance. Workers were randomly assigned for exposure to one of two treatment conditions from 23:00 hours to 07:00 hours: blue-enriched white light (17 000 K, 89 lux; n=36) or standard white light (4000 K, 84 lux; n=35). RESULTS Subjective and objective sleepiness increased during the night shift in both light conditions (p<0.05, ηp2=0.06-0.31), but no significant effects of light condition were observed. The 17 000 K light, however, did improve subjective sleepiness relative to the 4000 K condition when light exposure coincided with the time of the aMT6s peak (p<0.05, d=0.41-0.60). CONCLUSION This study suggests that, while blue-enriched light has potential to improve subjective sleepiness in night shift workers, further research is needed in the selection of light properties to maximise the benefits. TRIAL REGISTRATION NUMBER The Australian New Zealand Clinical Trials Registry ACTRN12610000097044 (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=320845&isReview=true).
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Affiliation(s)
- Tracey L Sletten
- Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,CRC for Alertness, Safety and Productivity, Clayton, Victoria, Australia
| | - Suzanne Ftouni
- Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,CRC for Alertness, Safety and Productivity, Clayton, Victoria, Australia
| | - Christian L Nicholas
- Melbourne School of Psychological Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Michelle Magee
- Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,CRC for Alertness, Safety and Productivity, Clayton, Victoria, Australia
| | - Ronald R Grunstein
- CRC for Alertness, Safety and Productivity, Clayton, Victoria, Australia.,Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia.,Department of Respiratory & Sleep Medicine, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
| | - Sally Ferguson
- Appleton Institute, Central Queensland University, Wayville, South Australia, Australia
| | - David J Kennaway
- Robinson Research Institute, School of Medicine, Discipline of Obstetrics and Gynaecology, University of Adelaide, Adelaide, South Australia, Australia
| | - Darren O'Brien
- Woolcock Institute of Medical Research, University of Sydney, Sydney, New South Wales, Australia.,Sydney Nursing School, University of Sydney, Sydney, New South Wales, Australia
| | - Steven W Lockley
- Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,CRC for Alertness, Safety and Productivity, Clayton, Victoria, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Shantha M W Rajaratnam
- Monash Institute of Cognitive and Clinical Neurosciences and School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,CRC for Alertness, Safety and Productivity, Clayton, Victoria, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
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Boardman JM, Bei B, Mellor A, Anderson C, Sletten TL, Drummond SP. 0262 THE ABILITY TO SELF-MONITOR PERFORMANCE DURING 60 HOURS OF TOTAL SLEEP DEPRIVATION AND FOLLOWING TWO NIGHTS RECOVERY. Sleep 2017. [DOI: 10.1093/sleepj/zsx050.261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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41
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Burns AC, Sletten TL, Magee M, Hawi Z, Nicholas CL, Saxena R, Ftouni S, Grunstein R, Kennaway D, Ferguson S, Lockley SW, Rajaratnam SW, Cain SW. 0029 BDNF VAL66MET POLYMORPHISM IMPACTS ALERTNESS AND PERFORMANCE IN SHIFT WORKERS. Sleep 2017. [DOI: 10.1093/sleepj/zsx050.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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42
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Mulhall MD, Sletten TL, Magee M, Howard ME, Rajaratnam SM. 0170 SLEEPINESS AND DRIVING INCIDENTS IN NURSES COMMUTING TO AND FROM WORK SHIFTS. Sleep 2017. [DOI: 10.1093/sleepj/zsx050.169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Segal AY, Sletten TL, Flynn-Evans EE, Lockley SW, Rajaratnam SMW. Daytime Exposure to Short- and Medium-Wavelength Light Did Not Improve Alertness and Neurobehavioral Performance. J Biol Rhythms 2016; 31:470-82. [PMID: 27474192 DOI: 10.1177/0748730416659953] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
While previous studies have demonstrated short-wavelength sensitivity to the acute alerting effects of light during the biological night, fewer studies have assessed the alerting effect of light during the daytime. This study assessed the wavelength-dependent sensitivity of the acute alerting effects of daytime light exposure following chronic sleep restriction in 60 young adults (29 men, 31 women; 22.5 ± 3.1 mean ± SD years). Participants were restricted to 5 h time in bed the night before laboratory admission and 3 h time in bed in the laboratory, aligned by wake time. Participants were randomized for exposure to 3 h total of either narrowband blue (λmax 458-480 nm, n = 23) or green light (λmax 551-555 nm, n = 25) of equal photon densities (2.8-8.4 × 10(13) photons/cm(2)/sec), beginning 3.25 h after waking, and compared with a darkness control (0 lux, n = 12). Subjective sleepiness (Karolinska Sleepiness Scale), sustained attention (auditory Psychomotor Vigilance Task), mood (Profile of Mood States Bi-Polar form), working memory (2-back task), selective attention (Stroop task), and polysomnographic and ocular sleepiness measures (Optalert) were assessed prior to, during, and after light exposure. We found no significant effect of light wavelength on these measures, with the exception of a single mood subscale. Further research is needed to optimize the characteristics of lighting systems to induce alerting effects during the daytime, taking into account potential interactions between homeostatic sleep pressure, circadian phase, and light responsiveness.
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Affiliation(s)
- Ahuva Y Segal
- Monash Institute of Cognitive and Clinical Neurosciences, Sleep and Circadian Medicine Laboratory, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Tracey L Sletten
- Monash Institute of Cognitive and Clinical Neurosciences, Sleep and Circadian Medicine Laboratory, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Erin E Flynn-Evans
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Boston, Massachusetts, USA Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Steven W Lockley
- Monash Institute of Cognitive and Clinical Neurosciences, Sleep and Circadian Medicine Laboratory, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Boston, Massachusetts, USA Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Shantha M W Rajaratnam
- Monash Institute of Cognitive and Clinical Neurosciences, Sleep and Circadian Medicine Laboratory, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Boston, Massachusetts, USA
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Magee M, Sletten TL, Ferguson SA, Grunstein RR, Anderson C, Kennaway DJ, Lockley SW, Rajaratnam SM. Associations between number of consecutive night shifts and impairment of neurobehavioral performance during a subsequent simulated night shift. Scand J Work Environ Health 2016; 42:217-27. [PMID: 27064758 DOI: 10.5271/sjweh.3560] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVE This study aimed to investigate sleep and circadian phase in the relationships between neurobehavioral performance and the number of consecutive shifts worked. METHODS Thirty-four shift workers [20 men, mean age 31.8 (SD 10.9) years] worked 2-7 consecutive night shifts immediately prior to a laboratory-based, simulated night shift. For 7 days prior, participants worked their usual shift sequence, and sleep was assessed with logs and actigraphy. Participants completed a 10-minute auditory psychomotor vigilance task (PVT) at the start (~21:00 hours) and end (~07:00 hours) of the simulated night shift. Mean reaction times (RT), number of lapses and RT distribution was compared between those who worked 2-3 consecutive night shifts versus those who worked 4-7 shifts. RESULTS Following 4-7 shifts, night shift workers had significantly longer mean RT at the start and end of shift, compared to those who worked 2-3 shifts. The slowest and fastest 10% RT were significantly slower at the start, but not end, of shift among participants who worked 4-7 nights. Those working 4-7 nights also demonstrated a broader RT distribution at the start and end of shift and had significantly slower RT based on cumulative distribution analysis (5 (th), 25 (th), 50 (th), 75 (th)percentiles at the start of shift; 75th percentile at the end of shift). No group differences in sleep parameters were found for 7 days and 24 hours prior to the simulated night shift. CONCLUSION A greater number of consecutive night shifts has a negative impact on neurobehavioral performance, likely due to cognitive slowing.
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Ftouni S, Sletten TL, Nicholas CL, Kennaway DJ, Lockley SW, Rajaratnam SMW. Ocular Measures of Sleepiness Are Increased in Night Shift Workers Undergoing a Simulated Night Shift Near the Peak Time of the 6-Sulfatoxymelatonin Rhythm. J Clin Sleep Med 2015; 11:1131-41. [PMID: 26094925 DOI: 10.5664/jcsm.5086] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 05/10/2015] [Indexed: 11/13/2022]
Abstract
STUDY OBJECTIVE The study examined the relationship between the circadian rhythm of 6-sulphatoxymelatonin (aMT6s) and ocular measures of sleepiness and neurobehavioral performance in shift workers undergoing a simulated night shift. METHODS Twenty-two shift workers (mean age 33.4, SD 11.8 years) were tested at approximately the beginning (20:00) and the end (05:55) of a simulated night shift in the laboratory. At the time point corresponding to the end of the simulated shift, 14 participants were classified as being within range of 6-sulphatoxymelatonin (aMT6s) acrophase--defined as 3 hours before or after aMT6s peak--and 8 were classified as outside aMT6s acrophase range. Participants completed the Karolinska Sleepiness Scale (KSS) and the auditory psychomotor vigilance task (aPVT). Waking electroencephalography (EEG) was recorded and infrared reflectance oculography was used to collect ocular measures of sleepiness: positive and negative amplitude/velocity ratio (PosAVR, NegAVR), mean blink total duration (BTD), the percentage of eye closure (%TEC), and a composite score of sleepiness levels (Johns Drowsiness Scale; JDS). RESULTS Participants who were tested within aMT6s acrophase range displayed higher levels of sleepiness on ocular measures (%TEC, BTD, PosAVR, JDS), objective sleepiness (EEG delta power frequency band), subjective ratings of sleepiness, and neurobehavioral performance, compared to those who were outside aMT6s acrophase range. CONCLUSIONS The study demonstrated that objective ocular measures of sleepiness are sensitive to circadian rhythm misalignment in shift workers.
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Affiliation(s)
- Suzanne Ftouni
- School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Tracey L Sletten
- School of Psychological Sciences, Monash University, Clayton, Victoria, Australia
| | - Christian L Nicholas
- Sleep Research Laboratory, Melbourne School of Psychological Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - David J Kennaway
- Robinson Research Institute, School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, South Australia, Australia
| | - Steven W Lockley
- School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts.,Division of Sleep Medicine, Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Shantha M W Rajaratnam
- School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.,Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts.,Division of Sleep Medicine, Department of Medicine, Harvard Medical School, Boston, Massachusetts
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46
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Sletten TL, Segal AY, Flynn-Evans EE, Lockley SW, Rajaratnam SMW. Inter-Individual Differences in Neurobehavioural Impairment following Sleep Restriction Are Associated with Circadian Rhythm Phase. PLoS One 2015; 10:e0128273. [PMID: 26043207 PMCID: PMC4456409 DOI: 10.1371/journal.pone.0128273] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 04/23/2015] [Indexed: 11/18/2022] Open
Abstract
Although sleep restriction is associated with decrements in daytime alertness and neurobehavioural performance, there are considerable inter-individual differences in the degree of impairment. This study examined the effects of short-term sleep restriction on neurobehavioural performance and sleepiness, and the associations between individual differences in impairments and circadian rhythm phase. Healthy adults (n = 43; 22 M) aged 22.5 ± 3.1 (mean ± SD) years maintained a regular 8:16 h sleep:wake routine for at least three weeks prior to laboratory admission. Sleep opportunity was restricted to 5 hours time-in-bed at home the night before admission and 3 hours time-in-bed in the laboratory, aligned by wake time. Hourly saliva samples were collected from 5.5 h before until 5 h after the pre-laboratory scheduled bedtime to assess dim light melatonin onset (DLMO) as a marker of circadian phase. Participants completed a 10-min auditory Psychomotor Vigilance Task (PVT), the Karolinska Sleepiness Scale (KSS) and had slow eye movements (SEM) measured by electrooculography two hours after waking. We observed substantial inter-individual variability in neurobehavioural performance, particularly in the number of PVT lapses. Increased PVT lapses (r = -0.468, p < 0.01), greater sleepiness (r = 0.510, p < 0.0001), and more slow eye movements (r = 0.375, p = 0.022) were significantly associated with later DLMO, consistent with participants waking at an earlier circadian phase. When the difference between DLMO and sleep onset was less than 2 hours, individuals were significantly more likely to have at least three attentional lapses the following morning. This study demonstrates that the phase of an individual’s circadian system is an important variable in predicting the degree of neurobehavioural performance impairment in the hours after waking following sleep restriction, and confirms that other factors influencing performance decrements require further investigation.
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Affiliation(s)
- Tracey L. Sletten
- Sleep and Circadian Medicine Laboratory, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
- * E-mail:
| | - Ahuva Y. Segal
- Sleep and Circadian Medicine Laboratory, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Erin E. Flynn-Evans
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Steven W. Lockley
- Sleep and Circadian Medicine Laboratory, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Shantha M. W. Rajaratnam
- Sleep and Circadian Medicine Laboratory, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
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Ashworth DK, Sletten TL, Junge M, Simpson K, Clarke D, Cunnington D, Rajaratnam SMW. A randomized controlled trial of cognitive behavioral therapy for insomnia: An effective treatment for comorbid insomnia and depression. J Couns Psychol 2015; 62:115-23. [DOI: 10.1037/cou0000059] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Sletten TL, Rajaratnam SM, Wright MJ, Zhu G, Naismith S, Martin NG, Hickie I. Genetic and environmental contributions to sleep-wake behavior in 12-year-old twins. Sleep 2013; 36:1715-22. [PMID: 24179306 PMCID: PMC3792390 DOI: 10.5665/sleep.3136] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES To examine the role of genetic and environmental factors on sleep behavior in 12-year-old twins matched for family environment. DESIGN Population-based twin cohort. SETTING Participants were assessed in their home environment. PATIENTS OR PARTICIPANTS One hundred thirty-two adolescent twins comprising 25 monozygotic (MZ) and 41 dizygotic (DZ) twin pairs; aged 12.2 ± 0.1 y (mean ± standard deviation). INTERVENTIONS N/A. MEASUREMENTS AND RESULTS For 2 weeks in their home environment, participants wore a wrist activity monitor and completed a daily sleep diary. Sleep diaries included reports of bedtime, wake time, and estimated sleep onset time. Mean timing, duration, and quality of sleep during the 2 weeks were calculated for each individual and compared within twin pairs. MZ twin correlations were higher than the DZ correlations for total sleep time (MZr = 0.64; DZr = 0.38) and sleep onset latency (MZr = 0.83; DZr = 0.53) and significantly higher for wake after sleep onset (MZr = 0.66; DZr = 0.04) and sleep efficiency (MZr = 0.82; DZr = 0.10). Univariate modeling showed additive genetic factors accounted for 65% of the variance in total sleep time, 83% in sleep onset latency, and 52% and 57% of the variance in wake after sleep onset and sleep efficiency, respectively. A predominant influence of shared environment was found on the timing of sleep (67% for sleep start time, 86% for sleep end time). CONCLUSIONS There is a strong genetic influence on the sleep-wake patterns of 12-year-old adolescents. Genes have a greater influence on sleep initiation and sleep maintenance and a smaller role in sleep timing, likely to be influenced by family environment.
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Affiliation(s)
- Tracey L. Sletten
- School of Psychology and Psychiatry, Monash University, Melbourne, Australia
| | | | | | - Gu Zhu
- Queensland Institute of Medical Research, Queensland, Australia
| | - Sharon Naismith
- Brain & Mind Research Institute, University of Sydney, Sydney, Australia
| | | | - Ian Hickie
- Brain & Mind Research Institute, University of Sydney, Sydney, Australia
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Roach GD, Darwent D, Sletten TL, Dawson D. Long-haul pilots use in-flight napping as a countermeasure to fatigue. Appl Ergon 2011; 42:214-218. [PMID: 20673572 DOI: 10.1016/j.apergo.2010.06.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 06/15/2010] [Indexed: 05/29/2023]
Abstract
The aim of this study was to examine the effects of fatigue on the amount of in-flight sleep obtained by airline pilots during long-haul duty periods. A total of 301 pilots collected sleep/wake and work/rest data for a period of at least 2 weeks each. Fatigue likelihood, i.e. low, moderate, high, or extreme, was estimated for each duty period based on a pilot's sleep/wake behaviour prior to duty and the time of day that the duty period occurred. Participants obtained 1.8 h of sleep (i.e. 27% of their rest time) during duty periods with low fatigue likelihood and 3.7 h of sleep (i.e. 54% of their rest time) during duty periods with extreme fatigue likelihood. These results indicate that (i) long-haul pilots obtain substantially more sleep during duty periods when fatigue is likely to be extreme than when fatigue is likely to be low and (ii) long-haul pilots use in-flight napping as a fatigue countermeasure, but more could be done to increase its efficacy.
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Affiliation(s)
- Gregory D Roach
- Centre for Sleep Research, University of South Australia, Adelaide SA, Australia.
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Sletten TL, Vincenzi S, Redman JR, Lockley SW, Rajaratnam SMW. Timing of sleep and its relationship with the endogenous melatonin rhythm. Front Neurol 2010; 1:137. [PMID: 21188265 PMCID: PMC3008942 DOI: 10.3389/fneur.2010.00137] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2010] [Accepted: 09/29/2010] [Indexed: 11/15/2022] Open
Abstract
While much research has investigated the effects of exogenous melatonin on sleep, less is known about the relationship between the timing of the endogenous melatonin rhythm and the sleep-wake cycle. Significant inter-individual variability in the phase relationship between sleep and melatonin rhythms has been reported although the extent to which the variability reflects intrinsic and/or environmental differences is unknown. We examined the effects of different sleeping schedules on the time of dim light melatonin onset (DLMO) in 28 young, healthy adults. Participants chose to maintain either an early (22:30-06:30 h) or a late (00:30-08:30 h) sleep schedule for at least 3 weeks prior to an overnight laboratory visit. Saliva samples were collected under dim light (<2 lux) and controlled posture conditions to determine salivary DLMO. The 2-h difference between groups in the enforced sleep-wake schedule was associated with a concomitant 1.75-h delay in DLMO. The mean phase relationship between sleep onset and DLMO remained constant (~2 h). The variance in DLMO time, however, was greater in the late group (range 4.5 h) compared to the early group (range 2.4 h) perhaps due to greater effect of environmental influences in delayed sleep types or greater intrinsic instability in their circadian system. The findings contribute to our understanding of individual differences in the human circadian clock and have important implications for the diagnosis and treatment of circadian rhythm sleep disorders, in particular if a greater normative range for phase angle of entrainment occurs in individuals with later sleep-wake schedules.
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Affiliation(s)
- Tracey L. Sletten
- School of Psychology and Psychiatry, Monash UniversityClayton, VIC, Australia
| | - Simon Vincenzi
- School of Psychology and Psychiatry, Monash UniversityClayton, VIC, Australia
| | - Jennifer R. Redman
- School of Psychology and Psychiatry, Monash UniversityClayton, VIC, Australia
| | - Steven W. Lockley
- School of Psychology and Psychiatry, Monash UniversityClayton, VIC, Australia
- Division of Sleep Medicine, Department of Medicine, Brigham and Women's HospitalBoston, MA, USA
- Division of Sleep Medicine, Harvard Medical SchoolBoston, MA, USA
| | - Shantha M. W. Rajaratnam
- School of Psychology and Psychiatry, Monash UniversityClayton, VIC, Australia
- Division of Sleep Medicine, Department of Medicine, Brigham and Women's HospitalBoston, MA, USA
- Division of Sleep Medicine, Harvard Medical SchoolBoston, MA, USA
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