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Smith SK, Kafashan M, Rios RL, Brown EN, Landsness EC, Guay CS, Palanca BJA. Daytime dexmedetomidine sedation with closed-loop acoustic stimulation alters slow wave sleep homeostasis in healthy adults. BJA OPEN 2024; 10:100276. [PMID: 38571816 PMCID: PMC10990715 DOI: 10.1016/j.bjao.2024.100276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 02/29/2024] [Indexed: 04/05/2024]
Abstract
Background The alpha-2 adrenergic agonist dexmedetomidine induces EEG patterns resembling those of non-rapid eye movement (NREM) sleep. Fulfilment of slow wave sleep (SWS) homeostatic needs would address the assumption that dexmedetomidine induces functional biomimetic sleep states. Methods In-home sleep EEG recordings were obtained from 13 healthy participants before and after dexmedetomidine sedation. Dexmedetomidine target-controlled infusions and closed-loop acoustic stimulation were implemented to induce and enhance EEG slow waves, respectively. EEG recordings during sedation and sleep were staged using modified American Academy of Sleep Medicine criteria. Slow wave activity (EEG power from 0.5 to 4 Hz) was computed for NREM stage 2 (N2) and NREM stage 3 (N3/SWS) epochs, with the aggregate partitioned into quintiles by time. The first slow wave activity quintile served as a surrogate for slow wave pressure, and the difference between the first and fifth quintiles as a measure of slow wave pressure dissipation. Results Compared with pre-sedation sleep, post-sedation sleep showed reduced N3 duration (mean difference of -17.1 min, 95% confidence interval -30.0 to -8.2, P=0.015). Dissipation of slow wave pressure was reduced (P=0.02). Changes in combined durations of N2 and N3 between pre- and post-sedation sleep correlated with total dexmedetomidine dose, (r=-0.61, P=0.03). Conclusions Daytime dexmedetomidine sedation and closed-loop acoustic stimulation targeting EEG slow waves reduced N3/SWS duration and measures of slow wave pressure dissipation on the post-sedation night in healthy young adults. Thus, the paired intervention induces sleep-like states that fulfil certain homeostatic NREM sleep needs in healthy young adults. Clinical trial registration ClinicalTrials.gov NCT04206059.
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Affiliation(s)
- S. Kendall Smith
- Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
- Center on Biological Rhythms and Sleep, Washington University in St. Louis, St. Louis, MO, USA
| | - MohammadMehdi Kafashan
- Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
- Center on Biological Rhythms and Sleep, Washington University in St. Louis, St. Louis, MO, USA
| | - Rachel L. Rios
- Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
- Center on Biological Rhythms and Sleep, Washington University in St. Louis, St. Louis, MO, USA
| | - Emery N. Brown
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Eric C. Landsness
- Center on Biological Rhythms and Sleep, Washington University in St. Louis, St. Louis, MO, USA
- Department of Neurology, Division of Sleep Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Christian S. Guay
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Ben Julian A. Palanca
- Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
- Center on Biological Rhythms and Sleep, Washington University in St. Louis, St. Louis, MO, USA
- Department of Psychiatry, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
- Division of Biology and Biomedical Sciences, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA
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David MCMM, Vieira GR, de Lima Leôncio LM, Dos Santos Neves L, Bezerra CG, de Mattos MSB, Dos Santos NF, Antunes RB, Silva DM, Araújo JF, de Matos RJB. Different sleep patterns during the COVID-19 pandemic: association with mood, exercise and light exposure. PSYCHOL HEALTH MED 2024; 29:140-152. [PMID: 36576314 DOI: 10.1080/13548506.2022.2159457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 12/13/2022] [Indexed: 12/29/2022]
Abstract
The aim was to evaluate the sleep-wake cycle pattern, mood, perceived stress and some behaviors, such as physical exercise and exposure to natural light of college students during the COVID-19 pandemic. This is a cross-sectional study conducted between June and August 2020 using an electronic form provided by Google. The sample consisted of undergraduate students aged between 18 and 30 years old and residents of the northeast region of Brazil. The students generally had sleepiness and poor sleep quality, high levels of anxiety, mild to moderate depressive symptoms and moderate perceived stress. Some of these aspects were worse in women. The college students showed three sleep patterns: one group had good sleep quality without excessive daytime sleepiness; another group had poor sleep quality, but no excessive daytime sleepiness; and a third group had high daytime sleepiness, and less expressive sleep quality impairment. Greater exposure to sunlight and practicing physical exercise predominated in individuals with better sleep quality, suggesting that they are protective factors. In addition, excessive daytime sleepiness and poor sleep quality were separately associated with higher anxiety, depression and stress perception levels, proving to be important aspects for care in order to favor mental health during the pandemic. In conclusion, it is suggested that the COVID-19 pandemic affected the sleep of college students in a heterogeneous way. The differentiated sleep patterns are associated with exposure to natural light and exercising.
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Affiliation(s)
- Mírian Celly Medeiros Miranda David
- Neural Plasticity, Environment and Behaviors Research Group, Federal University of Recôncavo da Bahia, Santo Antônio de Jesus, Brazil
- Posgraduate Program in Neuropsychiatry and Behavioral Sciences, Health Sciences Center, Federal University of Pernambuco, Recife, Brazil
| | - Gilberto Ramos Vieira
- Postgraduate Program in Physical Education, Health Sciences Center, Federal University of Pernambuco, Recife, Brazil
| | - Lívia Maria de Lima Leôncio
- Postgraduate Program in Nutrition, Physical Activity and Phenotypic Plasticity, Vitôria Academic Center, Federal University of Pernambuco, Vitôria de Santo Antão, Brazil
| | - Letycia Dos Santos Neves
- Postgraduate Program in Nutrition, Health Sciences Center, Federal University of Pernambuco, Recife, Brazi
| | - Clécia Gabriela Bezerra
- Multiprofessional Residency Program for Internalization of Health Care, Vitôria Academic Center, Federal University of Pernambuco, Vitôria de Santo Antão, Brazil
| | | | - Nataly Ferreira Dos Santos
- Neural Plasticity, Environment and Behaviors Research Group, Federal University of Recôncavo da Bahia, Santo Antônio de Jesus, Brazil
| | - Rodolfo Barbosa Antunes
- Department of Mathematics, Center of Exact and Natural Sciences, Federal University of Pernambuco, Recife, Brazil
| | - Daniel Moura Silva
- Department of Statistics and Informatics, Federal Rural University of Pernambuco, Recife, Brazil
| | - John Fontenele Araújo
- Department of Physiology and Behavior, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Rhowena Jane Barbosa de Matos
- Neural Plasticity, Environment and Behaviors Research Group, Federal University of Recôncavo da Bahia, Santo Antônio de Jesus, Brazil
- Posgraduate Program in Neuropsychiatry and Behavioral Sciences, Health Sciences Center, Federal University of Pernambuco, Recife, Brazil
- Health Sciences Center, Federal University of Recôncavo of Bahia, Santo Antônio de Jesus, Brazil
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Fang W, Le S, Han W, Peng-Jiao X, Shuai Y, Rui-Ling Z, Lin L, Ya-Hui X. Association between napping and cognitive impairment: A systematic review and meta-analysis. Sleep Med 2023; 111:146-159. [PMID: 37776585 DOI: 10.1016/j.sleep.2023.09.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/12/2023] [Accepted: 09/23/2023] [Indexed: 10/02/2023]
Abstract
STUDY OBJECTIVES Increasing evidence suggests that napping is associated with cognitive impairment and dementia, but the conclusions are inconsistent. Moreover, the extent of the risk is uncertain. We therefore conducted a systematic review and meta-analysis to quantify the connection between napping and cognitive impairment. METHODS We performed a systematic search of PubMed, EMBASE, Web of Science, and Cochrane Library for studies that were published up to June 2023, and assessed associations between napping and cognitive impairment. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated as the effect sizes for all studies. Heterogeneity and potential publication biases were assessed. RESULTS A total of 4535 papers were retrieved, with 20 reports assessing the relationships between napping and cognitive impairment. Pooled analysis indicated that napping was associated with dementia (OR = 1.14; 95% CI: 1.07-1.21). Importantly, we found that those napping longer than 30, 45, and 60 min/day were 35%, 41%, and 40%, respectively, more likely to have an increased risk of cognitive impairment (30 min: OR = 1.35; 95% CI: 1.24-1.48; 45 min: OR = 1.41; 95% CI: 1.27-1.58; 60 min: OR = 1.40; 95% CI: 1.26-1.56). North America and Europe showed that associations existed between napping and cognitive impairment (North America: OR = 1.15; 95% CI: 1.04-1.27; Europe: OR = 1.13; 95% CI: 1.08-1.18). CONCLUSIONS This meta-analysis indicated associations between long napping durations and cognitive impairment or dementia, suggesting that longer napping might be a potential risk factor of adverse cognitive outcomes.
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Affiliation(s)
- Wu Fang
- Department of Sleep Medicine, Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Shi Le
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Chinese Academy of Medical Sciences Research Unit (No. 2018RU006), Peking University, Beijing, China
| | - Wang Han
- Department of Sleep Medicine, Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Xu Peng-Jiao
- Department of Sleep Medicine, Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Yu Shuai
- Department of Sleep Medicine, Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Zhang Rui-Ling
- Department of Sleep Medicine, Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Lu Lin
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Chinese Academy of Medical Sciences Research Unit (No. 2018RU006), Peking University, Beijing, China; Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Beijing, China.
| | - Xu Ya-Hui
- Department of Sleep Medicine, Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, China.
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Kumral D, Matzerath A, Leonhart R, Schönauer M. Spindle-dependent memory consolidation in healthy adults: A meta-analysis. Neuropsychologia 2023; 189:108661. [PMID: 37597610 DOI: 10.1016/j.neuropsychologia.2023.108661] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 06/23/2023] [Accepted: 08/12/2023] [Indexed: 08/21/2023]
Abstract
Accumulating evidence suggests a central role for sleep spindles in the consolidation of new memories. However, no meta-analysis of the association between sleep spindles and memory performance has been conducted so far. Here, we report meta-analytical evidence for spindle-memory associations and investigate how multiple factors, including memory type, spindle type, spindle characteristics, and EEG topography affect this relationship. The literature search yielded 53 studies reporting 1427 effect sizes, resulting in a small to moderate effect for the average association. We further found that spindle-memory associations were significantly stronger for procedural memory than for declarative memory. Neither spindle types nor EEG scalp topography had an impact on the strength of the spindle-memory relation, but we observed a distinct functional role of global and fast sleep spindles, especially for procedural memory. We also found a moderation effect of spindle characteristics, with power showing the largest effect sizes. Collectively, our findings suggest that sleep spindles are involved in learning, thereby representing a general physiological mechanism for memory consolidation.
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Affiliation(s)
- Deniz Kumral
- Institute of Psychology, Neuropsychology, University of Freiburg, Freiburg Im Breisgau, Germany; Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
| | - Alina Matzerath
- Institute of Psychology, Neuropsychology, University of Freiburg, Freiburg Im Breisgau, Germany
| | - Rainer Leonhart
- Institute of Psychology, Social Psychology and Methodology, University of Freiburg, Freiburg Im Breisgau, Germany
| | - Monika Schönauer
- Institute of Psychology, Neuropsychology, University of Freiburg, Freiburg Im Breisgau, Germany; Bernstein Center Freiburg, Freiburg Im Breisgau, Germany
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Oriyama S. Effects of 90- and 30-min naps or a 120-min nap on alertness and performance: reanalysis of an existing pilot study. Sci Rep 2023; 13:9862. [PMID: 37332041 DOI: 10.1038/s41598-023-37061-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 06/15/2023] [Indexed: 06/20/2023] Open
Abstract
The aim of this study was to investigate alertness and cognitive performance immediately after and until the end of the night shift after taking a 120-min monophasic nap (One-nap) or a split 90-min and 30-min nap (Two-nap) during a 16-h simulated night shift, and the relationship between sleep quality and both alertness and performance. This study was performed in 41 females. Among them, 15 participants were included in the No-nap group, 14 in the One-nap group (22:00-00:00), and 12 in the Two-nap group (22:30-00:00 and 02:30-03:00). Participants were tested every hour from 16:00 to 09:00 for performance on the Uchida-Kraepelin test, as well as for subjective feelings of fatigue and drowsiness, body temperature, and heart rate variability. The shorter the sleep latency, the worse the alertness immediately after the 90-min nap. The 120-min and 30-min naps also revealed that prolonged total sleep time led to increased fatigue and drowsiness upon awakening. From 04:00 to 09:00, in the No-nap and One-nap groups, fatigue was higher than in the Two-nap group. The One-nap and Two-nap groups did not show improved morning performance. These results suggest that a split nap might improve drowsiness and fatigue during a long night shift.
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Affiliation(s)
- Sanae Oriyama
- Division of Nursing Science Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
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Daytime Variation of Chloral Hydrate-Associated Sedation Outcomes: A Propensity-Matched Cohort Study. J Clin Med 2023; 12:jcm12031245. [PMID: 36769893 PMCID: PMC9917952 DOI: 10.3390/jcm12031245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/31/2023] [Accepted: 02/02/2023] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Physiological processes influencing a drugs' efficacy change substantially over the course of the day. However, it is unclear whether there is an association between the sedative success rate of chloral hydrate and the time of day. We conducted a retrospective study of 41,831 cases, to determine if there was a difference in sedation success rate with chloral hydrate in children seen in the morning and afternoon. METHODS Patients who accepted the sedation service were included. Eligible patients were divided into two cohorts of morning and afternoon cases, according to the time of day when the initial dose of chloral hydrate was administered. To ensure that the two groups were comparable, a propensity score matching method was utilized. RESULTS The success rate with the initial dose of chloral hydrate was higher in patients who received sedation services in the afternoon. In the subgroup analysis, the afternoon cases had a higher sedation success rate compared to the morning cases in male patients; whereas, in female patients, no difference was detected between the morning versus afternoon cases. CONCLUSIONS These results show that the afternoon cases had a higher sedation success rate than the morning cases, despite the afternoon cases receiving relatively lower initial dose than the morning cases. However, the clinical significance remains to be discussed, and further prospective studies are needed to validate the findings.
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7
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Nelson ME, Lee S, Allen TD, Buxton OM, Almeida DM, Andel R. Goldilocks at work: Just the right amount of job demands may be needed for your sleep health. Sleep Health 2023; 9:40-48. [PMID: 36372656 PMCID: PMC9991992 DOI: 10.1016/j.sleh.2022.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 07/29/2022] [Accepted: 09/03/2022] [Indexed: 11/11/2022]
Abstract
OBJECTIVES It has been reported that job demands affect sleep, but how different levels of job demands affect sleep remains unclear. We examined whether curvilinear relationships exist between job demands and multiple sleep health outcomes. DESIGN Cross-sectional analyses with linear and quadratic effects, using self-administered survey data. SETTING A national sample of US adults. PARTICIPANTS Workers from Midlife in the United States Study (MIDUS2; n = 2927). MEASUREMENTS The Job Content Questionnaire assessed overall and 5 specific aspects of job demands (intensity, role conflict, work overload, time pressure, and interruptions). Habitual sleep health patterns across 5 dimensions (regularity, satisfaction/quality, daytime alertness, efficiency, and duration) were assessed. Age, sex, race/ethnicity, marital/partnered status, education, job tenure, work hours, body mass index, smoking status, and study sample were covariates. RESULTS There were significant linear and quadratic relationships between job demands and sleep outcomes. Specifically, the linear effects indicated that participants with higher job demands had worse sleep health, such as shorter duration, greater irregularity, greater inefficiency, and more sleep dissatisfaction. The quadratic effects, however, indicated that sleep regularity and efficiency outcomes were the best when participants' job demands were moderate rather than too low or too high. These effects were found for overall job demands as well as for specific aspects of job demands. Stratified analyses further revealed that these curvilinear associations were mainly driven by participants with low job control. CONCLUSIONS Moderate levels of job demands, especially if combined with adequate job control, are related to optimal sleep health.
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Affiliation(s)
- Monica E Nelson
- School of Aging Studies, University of South Florida, Tampa, Florida, USA.
| | - Soomi Lee
- School of Aging Studies, University of South Florida, Tampa, Florida, USA
| | - Tammy D Allen
- Department of Psychology, University of South Florida, Tampa, Florida, USA
| | - Orfeu M Buxton
- Department of Biobehavioral Health, Pennsylvania State University, University Park, Pennsylvania, USA
| | - David M Almeida
- Department of Human Development and Family Studies, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Ross Andel
- Center for Innovation in Healthy and Resilient Aging, Edson College of Nursing and Health Innovation, Arizona State University, Phoenix, Arizona, USA; Department of Neurology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Czech Republic; International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic
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8
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Leong RLF, Lo JC, Chee MWL. Systematic review and meta-analyses on the effects of afternoon napping on cognition. Sleep Med Rev 2022; 65:101666. [PMID: 36041284 DOI: 10.1016/j.smrv.2022.101666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 06/09/2022] [Accepted: 06/21/2022] [Indexed: 10/15/2022]
Abstract
Naps are increasingly considered a means to boost cognitive performance. We quantified the cognitive effects of napping in 60 samples from 54 studies. 52 samples evaluated memory. We first evaluated effect sizes for all tests together, before separately assessing their effects on memory, vigilance, speed of processing and executive function. We next examined whether nap effects were moderated by study features of age, nap length, nap start time, habituality and prior sleep restriction. Naps showed significant benefits for the total aggregate of cognitive tests (Cohen's d = 0.379, CI95 = 0.296-0.462). Significant domain specific effects were present for declarative (Cohen's d = 0.376, CI95 = 0.269-0.482) and procedural memory (Cohen's d = 0.494, CI95 = 0.301-0.686), vigilance (Cohen's d = 0.610, CI95 = 0.291-0.929) and speed of processing (Cohen's d = 0.211, CI95 = 0.052-0.369). There were no significant moderation effects of any of the study features. Nap effects were of comparable magnitude across subgroups of each of the 5 moderators (Q values = 0.009 to 8.572, p values > 0.116). Afternoon naps have a small to medium benefit over multiple cognitive tests. These effects transcend age, nap duration and tentatively, habituality and prior nocturnal sleep.
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Affiliation(s)
- Ruth L F Leong
- Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
| | - June C Lo
- Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Michael W L Chee
- Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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9
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Riveros-Rivera A, Penzel T, Gunga HC, Opatz O, Paul F, Klug L, Boschmann M, Mähler A. Hypoxia Differentially Affects Healthy Men and Women During a Daytime Nap With a Dose-Response Relationship: a Randomized, Cross-Over Pilot Study. Front Physiol 2022; 13:899636. [PMID: 35685284 PMCID: PMC9171024 DOI: 10.3389/fphys.2022.899636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 04/18/2022] [Indexed: 11/13/2022] Open
Abstract
Context: The use of daytime napping as a countermeasure in sleep disturbances has been recommended but its physiological evaluation at high altitude is limited. Objective: To evaluate the neuroendocrine response to hypoxic stress during a daytime nap and its cognitive impact. Design, Subject, and Setting: Randomized, single-blind, three period cross-over pilot study conducted with 15 healthy lowlander subjects (8 women) with a mean (SD) age of 29(6) years (Clinicaltrials identifier: NCT04146857, https://clinicaltrials.gov/ct2/show/NCT04146857?cond=napping&draw=3&rank=12). Interventions: Volunteers underwent a polysomnography, hematological and cognitive evaluation around a 90 min midday nap, being allocated to a randomized sequence of three conditions: normobaric normoxia (NN), normobaric hypoxia at FiO2 14.7% (NH15) and 12.5% (NH13), with a washout period of 1 week between conditions. Results: Primary outcome was the interbeat period measured by the RR interval with electrocardiogram. Compared to normobaric normoxia, RR during napping was shortened by 57 and 206 ms under NH15 and NH13 conditions, respectively (p < 0.001). Sympathetic predominance was evident by heart rate variability analysis and increased epinephrine levels. Concomitantly, there were significant changes in endocrine parameters such as erythropoietin (∼6 UI/L) and cortisol (∼100 nmol/L) (NH13 vs. NN, p < 0.001). Cognitive evaluation revealed changes in the color-word Stroop test. Additionally, although sleep efficiency was preserved, polysomnography showed lesser deep sleep and REM sleep, and periodic breathing, predominantly in men. Conclusion: Although napping in simulated altitude does not appear to significantly affect cognitive performance, sex-dependent changes in cardiac autonomic modulation and respiratory pattern should be considered before napping is prescribed as a countermeasure.
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Affiliation(s)
- Alain Riveros-Rivera
- Center for Space Medicine and Extreme Environments Berlin, Institute of Physiology, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Physiological Sciences, Faculty of Medicine, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Thomas Penzel
- Interdisciplinary Center of Sleep Medicine, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Hanns-Christian Gunga
- Center for Space Medicine and Extreme Environments Berlin, Institute of Physiology, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Oliver Opatz
- Center for Space Medicine and Extreme Environments Berlin, Institute of Physiology, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Friedemann Paul
- Experimental and Clinical Research Center, A Cooperation Between the Max-Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Lars Klug
- Experimental and Clinical Research Center, A Cooperation Between the Max-Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Michael Boschmann
- Experimental and Clinical Research Center, A Cooperation Between the Max-Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Anja Mähler
- Experimental and Clinical Research Center, A Cooperation Between the Max-Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
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10
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Aghayan Golkashani H, Leong RLF, Ghorbani S, Ong JL, Fernández G, Chee MWL. A sleep schedule incorporating naps benefits the transformation of hierarchical knowledge. Sleep 2022; 45:6516991. [PMID: 35090173 PMCID: PMC8996033 DOI: 10.1093/sleep/zsac025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/14/2021] [Indexed: 11/14/2022] Open
Abstract
Abstract
Study Objectives
The learning brain establishes schemas (knowledge structures) that benefit subsequent learning. We investigated how sleep and having a schema might benefit initial learning followed by rearranged and expanded memoranda. We concurrently examined the contributions of sleep spindles and slow-wave sleep to learning outcomes.
Methods
Fifty-three adolescents were randomly assigned to an 8 h Nap schedule (6.5 h nocturnal sleep with a 90-minute daytime nap) or an 8 h No-Nap, nocturnal-only sleep schedule. The study spanned 14 nights, simulating successive school weeks. We utilized a transitive inference task involving hierarchically ordered faces. Initial learning to set up the schema was followed by rearrangement of the hierarchy (accommodation) and hierarchy expansion (assimilation). The expanded sequence was restudied. Recall of hierarchical knowledge was tested after initial learning and at multiple points for all subsequent phases. As a control, both groups underwent a No-schema condition where the hierarchy was introduced and modified without opportunity to set up a schema. Electroencephalography accompanied the multiple sleep opportunities.
Results
There were main effects of Nap schedule and Schema condition evidenced by superior recall of initial learning, reordered and expanded memoranda. Improved recall was consistently associated with higher fast spindle density but not slow-wave measures. This was true for both nocturnal sleep and daytime naps.
Conclusion
A sleep schedule incorporating regular nap opportunities compared to one that only had nocturnal sleep benefited building of robust and flexible schemas, facilitating recall of the subsequently rearranged and expanded structured knowledge. These benefits appear to be strongly associated with fast spindles.
Clinical Trial registration
NCT04044885 (https://clinicaltrials.gov/ct2/show/NCT04044885).
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Affiliation(s)
- Hosein Aghayan Golkashani
- Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Ruth L F Leong
- Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Shohreh Ghorbani
- Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Ju Lynn Ong
- Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Guillén Fernández
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Michael W L Chee
- Centre for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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Brager AJ. Commentary Piece: Commanding fatigue management in the United States Army's fleet of commercial truck drivers. Sleep Health 2022; 8:261-262. [DOI: 10.1016/j.sleh.2022.03.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 02/23/2022] [Accepted: 03/08/2022] [Indexed: 11/28/2022]
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Mograss M, Abi‐Jaoude J, Frimpong E, Chalati D, Moretto U, Tarelli L, Lim A, Dang‐Vu TT. The effects of napping on night‐time sleep in healthy young adults. J Sleep Res 2022; 31:e13578. [PMID: 35253300 DOI: 10.1111/jsr.13578] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/19/2022] [Accepted: 02/16/2022] [Indexed: 11/29/2022]
Abstract
The discrepancies in the effects of napping on sleep quality may be due to differences in methodologies, napping behaviours, and daytime activity levels across studies. We determined whether napping behaviours and daytime activity levels are associated with night-time sleep fragmentation and sleep quality in young adults. A total of 62 healthy adults (mean [SD] age 23.5 [4.2] years) completed screening questionnaires for sleep habits, physical activity, medical and psychological history. Actigraphy was used to record sleep including naps. The fragmentation algorithm (KRA ) was applied to the actigraphic data to measure night-time sleep fragmentation. We classified participants' nap frequency as "non-nappers" (0 naps/8 days), "moderate nappers" (1-2 naps/8 days) or "frequent nappers" (≥3 naps/8 days) naps. Nap duration was defined as "short" (≤60 min) or "long" (>60 min). Naps' proximity to the night sleep episode was defined as "early" (≥7 h) and "late" (<7 h) naps. Outcome variables were night-time KRA and actigraphic sleep variables. Frequent nappers had a significantly higher KRA than moderate nappers (p < 0.01) and non-nappers (p < 0.02). Late naps were associated with poorer measures of night sleep quality versus early naps (all p ≤ 0.02). Nap duration and daytime activity were not associated with significant differences in the outcome variables (all p > 0.05). KRA correlated with sleep duration, sleep efficiency, and awakenings (r = -0.32, -0.32, and 0.53, respectively; all p < 0.05). Frequent napping and late naps may be associated with increased sleep fragmentation and poorer sleep quality, reflected in longer sleep onsets and increased awakenings. These findings have implications for public health sleep hygiene recommendations.
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Affiliation(s)
- Melodee Mograss
- Department of Psychology Concordia University Montreal Quebec Canada
- Department of Health Kinesiology and Applied Physiology Concordia University Montreal Quebec Canada
- Concordia University PERFORM Centre Montreal Quebec Canada
- Centre de Recherche de l’Institut Universitaire de Gériatrie de Montréal Montreal Quebec Canada
| | - Joanne Abi‐Jaoude
- Department of Psychology Concordia University Montreal Quebec Canada
- Concordia University PERFORM Centre Montreal Quebec Canada
| | - Emmanuel Frimpong
- Department of Health Kinesiology and Applied Physiology Concordia University Montreal Quebec Canada
| | - Diaa Chalati
- Concordia University PERFORM Centre Montreal Quebec Canada
| | | | - Lukia Tarelli
- Department of Psychology Concordia University Montreal Quebec Canada
- Concordia University PERFORM Centre Montreal Quebec Canada
| | - Andrew Lim
- Sunnybrook Health Sciences Centre University of Toronto Toronto Ontario Canada
| | - Thien Thanh Dang‐Vu
- Department of Psychology Concordia University Montreal Quebec Canada
- Department of Health Kinesiology and Applied Physiology Concordia University Montreal Quebec Canada
- Concordia University PERFORM Centre Montreal Quebec Canada
- Centre de Recherche de l’Institut Universitaire de Gériatrie de Montréal Montreal Quebec Canada
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