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Spitschan M. Selecting, implementing and evaluating control and placebo conditions in light therapy and light-based interventions. Ann Med 2024; 56:2298875. [PMID: 38329797 PMCID: PMC10854444 DOI: 10.1080/07853890.2023.2298875] [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: 09/21/2023] [Accepted: 12/20/2023] [Indexed: 02/09/2024] Open
Abstract
Introduction: Light profoundly influences human physiology, behaviour and cognition by affecting various functions through light-sensitive cells in the retina. Light therapy has proven effective in treating seasonal depression and other disorders. However, designing appropriate control conditions for light-based interventions remains a challenge.Materials and methods: This article presents a novel framework for selecting, implementing and evaluating control conditions in light studies, offering theoretical foundations and practical guidance. It reviews the fundamentals of photoreception and discusses control strategies such as dim light, darkness, different wavelengths, spectral composition and metameric conditions. Special cases like dynamic lighting, simulated dawn and dusk, complex interventions and studies involving blind or visually impaired patients are also considered.Results: The practical guide outlines steps for selection, implementation, evaluation and reporting, emphasizing the importance of α-opic calculations and physiological validation.Conclusion: In conclusion, constructing effective control conditions is crucial for demonstrating the efficacy of light interventions in various research scenarios.
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Affiliation(s)
- Manuel Spitschan
- Max Planck Institute for Biological Cybernetics, Translational Sensory & Circadian Neuroscience, Tübingen, Germany
- Technical University of Munich, TUM School of Medicine and Health, Chronobiology & Health, Munich, Germany
- Technical University of Munich, TUM Institute for Advanced Study (TUM-IAS), Garching, Germany
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2
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Xu M, Papatsimpa C, Schlangen L, Linnartz JP. Improving adjustment to daylight saving time transitions with light. Sci Rep 2024; 14:15001. [PMID: 38951618 DOI: 10.1038/s41598-024-65705-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 06/24/2024] [Indexed: 07/03/2024] Open
Abstract
Daylight saving time (DST) is currently utilized in many countries with the rationale that it enhances the alignment between daylight hours and activity peaks in the population. The act of transitioning into and out of DST introduces disruptions to the circadian rhythm, thereby impacting sleep and overall health. Despite the substantial number of individuals affected, the consequences of this circadian disruption have often been overlooked. Here, we employ a mathematical model of the human circadian pacemaker to elucidate how the biological clock interacts with daytime and evening exposures to both natural and electrical light. This interaction plays a crucial role in determining the adaptation to the 1 hour time zone shift imposed by the transition to or from DST. In global discussions about DST, there is a prevailing assumption that individuals easily adjust to DST transitions despite a few studies indicating that the human circadian system requires several days to fully adjust to a DST transition. Our study highlights that evening light exposure changes can be the main driving force for re-entrainment, with chronobiological models predicting that people with longer intrinsic period (i.e. later chronotype) entrain more slowly to transitions to or from DST as compared to people with a shorter intrinsic period (earlier chronotype). Moreover, the model forecasts large inter-individual differences in the adaptation speed, in particular during the spring transition. The predictions derived from our model offer circadian biology-based recommendations for light exposure strategies that facilitate a more rapid adaptation to DST-related transitions or travel across a single time zone. As such, our study contributes valuable insights to the ongoing discourse on DST and its implications for human circadian rhythms.
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Affiliation(s)
- Mengzhu Xu
- Lighting and IoT lab, department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | | | - Luc Schlangen
- Human-Technology Interaction Group, department of Industrial Engineering and Innovation Sciences, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Jean-Paul Linnartz
- Lighting and IoT lab, department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
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3
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Mohammadian N, Didikoglu A, Beach C, Wright P, Mouland JW, Martial FP, Johnson S, van Tongeren M, Brown TM, Lucas RJ, Casson AJ. A Wrist-Worn Internet of Things Sensor Node for Wearable Equivalent Daylight Illuminance Monitoring. IEEE INTERNET OF THINGS JOURNAL 2024; 11:16148-16157. [PMID: 38765485 PMCID: PMC11100858 DOI: 10.1109/jiot.2024.3355330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 11/13/2023] [Accepted: 01/03/2024] [Indexed: 05/22/2024]
Abstract
Light exposure is a vital regulator of physiology and behavior in humans. However, monitoring of light exposure is not included in current wearable Internet of Things (IoT) devices, and only recently have international standards defined [Formula: see text] -optic equivalent daylight illuminance (EDI) measures for how the eye responds to light. This article reports a wearable light sensor node that can be incorporated into the IoT to provide monitoring of EDI exposure in real-world settings. We present the system design, electronic performance testing, and accuracy of EDI measurements when compared to a calibrated spectral source. This includes consideration of the directional response of the sensor, and a comparison of performance when placed on different parts of the body, and a demonstration of practical use over 7 days. Our device operates for 3.5 days between charges, with a sampling period of 30 s. It has 10 channels of measurement, over the range 415-910 nm, balancing accuracy and cost considerations. Measured [Formula: see text]-opic EDI results for 13 devices show a mean absolute error of less than 0.07 log lx, and a minimum between device correlation of 0.99. These findings demonstrate that accurate light sensing is feasible, including at wrist worn locations. We provide an experimental platform for use in future investigations in real-world light exposure monitoring and IoT-based lighting control.
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Affiliation(s)
- Navid Mohammadian
- Henry Royce Institute for Advanced Materials and the Department of Electrical and Electronic EngineeringSchool of EngineeringThe University of ManchesterM13 9PLManchesterU.K.
| | - Altug Didikoglu
- Division of Neuroscience, School of Biological SciencesThe University of ManchesterM13 9PLManchesterU.K.
| | - Christopher Beach
- Henry Royce Institute for Advanced Materials and the Department of Electrical and Electronic EngineeringSchool of EngineeringThe University of ManchesterM13 9PLManchesterU.K.
| | - Paul Wright
- Department of Electrical and Electronic EngineeringSchool of EngineeringThe University of ManchesterM13 9PLManchesterU.K.
| | - Joshua W. Mouland
- Division of Neuroscience, School of Biological SciencesThe University of ManchesterM13 9PLManchesterU.K.
| | - Franck P. Martial
- Division of Neuroscience, School of Biological SciencesThe University of ManchesterM13 9PLManchesterU.K.
| | - Sheena Johnson
- People, Management and Organisation Division, Alliance Manchester Business SchoolThe University of ManchesterM13 9PLManchesterU.K.
| | - Martie van Tongeren
- Division of Population Health, Health Services Research and Primary Care, School of Health SciencesThe University of ManchesterM13 9PLManchesterU.K.
| | - Timothy M. Brown
- Division of Diabetes, Endocrinology and Gastroenterology, School of Medical SciencesThe University of ManchesterM13 9PLManchesterU.K.
| | - Robert J. Lucas
- Division of Neuroscience, School of Biological SciencesThe University of ManchesterM13 9PLManchesterU.K.
| | - Alexander J. Casson
- Henry Royce Institute for Advanced Materials and the Department of Electrical and Electronic EngineeringSchool of EngineeringThe University of ManchesterM13 9PLManchesterU.K.
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4
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Spitschan M, Vidafar P, Cain SW, Phillips AJK, Lambert BC. Power Analysis for Human Melatonin Suppression Experiments. Clocks Sleep 2024; 6:114-128. [PMID: 38534797 DOI: 10.3390/clockssleep6010009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/07/2024] [Accepted: 02/10/2024] [Indexed: 03/28/2024] Open
Abstract
In humans, the nocturnal secretion of melatonin by the pineal gland is suppressed by ocular exposure to light. In the laboratory, melatonin suppression is a biomarker for this neuroendocrine pathway. Recent work has found that individuals differ substantially in their melatonin-suppressive response to light, with the most sensitive individuals being up to 60 times more sensitive than the least sensitive individuals. Planning experiments with melatonin suppression as an outcome needs to incorporate these individual differences, particularly in common resource-limited scenarios where running within-subjects studies at multiple light levels is costly and resource-intensive and may not be feasible with respect to participant compliance. Here, we present a novel framework for virtual laboratory melatonin suppression experiments, incorporating a Bayesian statistical model. We provide a Shiny web app for power analyses that allows users to modify various experimental parameters (sample size, individual-level heterogeneity, statistical significance threshold, light levels), and simulate a systematic shift in sensitivity (e.g., due to a pharmacological or other intervention). Our framework helps experimenters to design compelling and robust studies, offering novel insights into the underlying biological variability in melatonin suppression relevant for practical applications.
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Affiliation(s)
- Manuel Spitschan
- Department of Health and Sport Sciences, TUM School of Medicine and Health, Technical University of Munich, 80992 Munich, Germany
- TUM Institute for Advanced Study (TUM-IAS), Technical University of Munich, 85748 Garching, Germany
- Max Planck Research Group Translational Sensory and Circadian Neuroscience, Max Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany
| | - Parisa Vidafar
- Faculty of Medicine and Health, Central Clinical School, University of Sydney, Sydney, NSW 2006, Australia
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Sean W Cain
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Andrew J K Phillips
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Ben C Lambert
- Department of Statistics, University of Oxford, Oxford OX1 3LB, UK
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5
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Hraška J, Čurpek J. The practical implications of the EN 17037 minimum target daylight factor for building design and urban daylight in several European countries. Heliyon 2024; 10:e23297. [PMID: 38192874 PMCID: PMC10773465 DOI: 10.1016/j.heliyon.2023.e23297] [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: 09/21/2023] [Revised: 11/20/2023] [Accepted: 11/30/2023] [Indexed: 01/10/2024] Open
Abstract
Sufficient daylight in the indoor environment of buildings is important not only for vision and well-being as daylight also has significant non-visual effects on the human organism. The provision of daylight in the interiors of buildings significantly affects the architectural and urban parameters of the building environment. Harmonized EN 17037 introduced a number of changes and ambiguities to the relatively established principles of incorporating daylight in buildings in several European countries; these were significant for both architects and other stakeholders. This paper compares the long-standing practice and historical context of daylight provision according to the criteria of national standards in selected European countries (Germany, Czech Republic, Slovak republic, Sweden) with the minimum target daylight factor according to the harmonized EN 17037. The consequences of the methodological differences and design criteria of daylight provision are presented in case studies of the assessment of the daylight in residential rooms and typical school classrooms. Daylight factor and lighting distribution are analyzed for different room scenarios, different window configurations and obstruction angles according to local standards in the mentioned European countries versus EN 17037. The paper also highlights the practical impact of the EN 17037 criteria on building design and the extent of façade obstruction.
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Affiliation(s)
- Jozef Hraška
- Faculty of Civil Engineering, Slovak University of Technology, Bratislava 810 05, Slovakia
| | - Jakub Čurpek
- Faculty of Civil Engineering, Slovak University of Technology, Bratislava 810 05, Slovakia
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6
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Zeng X, Soreze TSC, Ballegaard M, Petersen PM. Integrative Lighting Aimed at Patients with Psychiatric and Neurological Disorders. Clocks Sleep 2023; 5:806-830. [PMID: 38131751 PMCID: PMC10742818 DOI: 10.3390/clockssleep5040052] [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: 11/19/2023] [Revised: 12/07/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023] Open
Abstract
The purpose of this paper is to investigate the impact of circadian lighting-induced melatonin suppression on patients with psychiatric and neurological disorders in hospital wards by using an ad-hoc metrology framework and the subsequent metrics formalized by the CIE in 2018. A measurement scheme was conducted in hospital ward rooms in the Department of Neurology, Zealand University Hospital, at Roskilde in Denmark, to evaluate the photometric and colorimetric characteristics of the lighting system, as well as its influence on the circadian rhythm of the occupants. The measurement scheme included point measurements and data logging, using a spectrophotometer mounted on a tripod with adjustable height to assess the newly installed circadian lighting system. The measured spectra were uploaded to the Luox platform to calculate illuminance, CCT, MEDI, etc., in accordance with the CIE S026 standard. Furthermore, the MLIT based on MEDI data logging results was calculated. In addition to CIE S026, we have investigated the usefulness of melatonin suppression models for the assessment of circadian performance regarding measured light. From the results, the lighting conditions in the patient room for both minimal and abundant daylight access were evaluated and compared; we found that access to daylight is essential for both illumination and circadian entrainment. It can be concluded that the measurement scheme, together with the use of the Luox platform and Canva template, is suitable for the accurate and satisfactory measurement of integrative lighting that aligns with CIE requirements and recommendations.
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Affiliation(s)
- Xinxi Zeng
- Department of Electrical and Photonics Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (X.Z.); (P.M.P.)
| | - Thierry Silvio Claude Soreze
- Department of Electrical and Photonics Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (X.Z.); (P.M.P.)
| | - Martin Ballegaard
- Department of Neurology, Copenhagen University Hospital—Zealand University Hospital Roskilde, 4000 Roskilde, Denmark;
- Department of Clinical Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Paul Michael Petersen
- Department of Electrical and Photonics Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark; (X.Z.); (P.M.P.)
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7
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Hibberd TJ, Ramsay S, Spencer-Merris P, Dinning PG, Zagorodnyuk VP, Spencer NJ. Circadian rhythms in colonic function. Front Physiol 2023; 14:1239278. [PMID: 37711458 PMCID: PMC10498548 DOI: 10.3389/fphys.2023.1239278] [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: 06/13/2023] [Accepted: 08/17/2023] [Indexed: 09/16/2023] Open
Abstract
A rhythmic expression of clock genes occurs within the cells of multiple organs and tissues throughout the body, termed "peripheral clocks." Peripheral clocks are subject to entrainment by a multitude of factors, many of which are directly or indirectly controlled by the light-entrainable clock located in the suprachiasmatic nucleus of the hypothalamus. Peripheral clocks occur in the gastrointestinal tract, notably the epithelia whose functions include regulation of absorption, permeability, and secretion of hormones; and in the myenteric plexus, which is the intrinsic neural network principally responsible for the coordination of muscular activity in the gut. This review focuses on the physiological circadian variation of major colonic functions and their entraining mechanisms, including colonic motility, absorption, hormone secretion, permeability, and pain signalling. Pathophysiological states such as irritable bowel syndrome and ulcerative colitis and their interactions with circadian rhythmicity are also described. Finally, the classic circadian hormone melatonin is discussed, which is expressed in the gut in greater quantities than the pineal gland, and whose exogenous use has been of therapeutic interest in treating colonic pathophysiological states, including those exacerbated by chronic circadian disruption.
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Affiliation(s)
- Timothy J. Hibberd
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Stewart Ramsay
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | | | - Phil G. Dinning
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
- Colorectal Surgical Unit, Division of Surgery, Flinders Medical Centre, Adelaide, SA, Australia
| | | | - Nick J. Spencer
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
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8
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Schöllhorn I, Deuring G, Stefani O, Strumberger MA, Rosburg T, Lemoine P, Pross A, Wingert B, Mager R, Cajochen C. Effects of nature-adapted lighting solutions ("Virtual Sky") on subjective and objective correlates of sleepiness, well-being, visual and cognitive performance at the workplace. PLoS One 2023; 18:e0288690. [PMID: 37535612 PMCID: PMC10399894 DOI: 10.1371/journal.pone.0288690] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 07/03/2023] [Indexed: 08/05/2023] Open
Abstract
Exposure to natural daylight benefits human well-being, alertness, circadian rhythms and sleep. Many workplaces have limited or no access to daylight. Thus, we implemented a light-panel ("Virtual Sky"), which reproduced nature-adapted light scenarios. In a laboratory office environment, three lighting scenarios were presented during the day: two lighting conditions with nature-adapted spectral light distributions, one with static and one with dynamic clouds, and a standard office lighting condition. We compared the impact of the three lighting scenarios on subjective and objective measures of alertness, cognitive performance, wellbeing, visual comfort, contrast sensitivity, and cortisol levels in 18 healthy young male volunteers in a within-participant cross-over study design. We found no evidence that an 8-h lighting scenario with static or dynamic clouds during the waking day (9am-5pm) was associated with any significant effect on objective and/or subjective alertness, cognitive performance and morning cortisol concentrations compared to standard workplace lighting. However, the dynamic light scenario was accompanied with lower levels of perceived tensionafter completing cognitive tasks and less effort to concentrate compared to the static lighting scenarios. Our findings suggest that apart from smaller effects on tension and concentration effort, nature-adapted lighting conditions did not improve daytime alertness and cognitive performance in healthy well-rested young participants, as compared to standard office lighting.
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Affiliation(s)
- Isabel Schöllhorn
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland
- Research Platform Molecular and Cognitive Neurosciences (MCN), University of Basel, Basel, Switzerland
| | - Gunnar Deuring
- Forensic Department, Basel University, University Psychiatric Clinics, Basel, Switzerland
| | - Oliver Stefani
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland
- Research Platform Molecular and Cognitive Neurosciences (MCN), University of Basel, Basel, Switzerland
| | - Michael A Strumberger
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland
- Research Platform Molecular and Cognitive Neurosciences (MCN), University of Basel, Basel, Switzerland
| | - Timm Rosburg
- Department of Clinical Research, Division of Clinical Epidemiology, EbIM Research & Education, University of Basel Hospital, Basel, Switzerland
| | - Patrick Lemoine
- Forensic Department, Basel University, University Psychiatric Clinics, Basel, Switzerland
| | - Achim Pross
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland
| | - Benjamin Wingert
- Fraunhofer-Institute for Industrial Engineering, Stuttgart, Germany
| | - Ralph Mager
- Forensic Department, Basel University, University Psychiatric Clinics, Basel, Switzerland
| | - Christian Cajochen
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland
- Research Platform Molecular and Cognitive Neurosciences (MCN), University of Basel, Basel, Switzerland
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9
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Xu W, Wu P, Yao Q, Zhang R, Li P, Bao L, Wang C, Chen S, Zhang Y, Shen Y. Does the smartphone's eye protection mode work? OPTICS EXPRESS 2023; 31:10420-10433. [PMID: 37157589 DOI: 10.1364/oe.485195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
People spend about 5-8 hours per day on phones, causing circadian disruption and eye fatigue, thus raising a great need for comfort and health. Most phones have eye protection modes, claiming a potential eye protection effect. To examine the effectiveness, we investigated the color quality, namely gamut area and just noticeable color difference (JNCD), and circadian effect, namely equivalent melanopic lux (EML) and melanopic daylight efficacy ratio (MDER), characteristics of two smartphones: iPhone 13 and HUAWEI P30, in normal and eye protection mode. The results show that the circadian effect is inversely proportional to color quality when the iPhone 13 and HUAWEI P30 changed from normal to eye protection mode. The gamut area changed from 102.51% to 82.5% sRGB and 100.36% to 84.55% sRGB, respectively. The EML and MDER decreased by 13 and 15, and, 0.50 and 0.38, respectively, affected by the eye protection mode and screen luminance. The EML and JNCD results in different modes show that the eye protection mode benefits the nighttime circadian effect at the cost of the image quality. This study provides a way to precisely assess the image quality and circadian effect of displays and elucidates the tradeoff relationship between them.
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10
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Vidafar P, Spitschan M. Light on Shedding: A Review of Sex and Menstrual Cycle Differences in the Physiological Effects of Light in Humans. J Biol Rhythms 2023; 38:15-33. [PMID: 36367137 PMCID: PMC9902977 DOI: 10.1177/07487304221126785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The human circadian system responds to light as low as 30 photopic lux. Furthermore, recent evidence shows that there are huge individual differences in light sensitivity, which may help to explain why some people are more susceptible to sleep and circadian disruption than others. The biological mechanisms underlying the differences in light sensitivity remain largely unknown. A key variable of interest in understanding these individual differences in light sensitivity is biological sex. It is possible that in humans, males and females differ in their sensitivity to light, but the evidence is inconclusive. This is in part due to the historic exclusion of women in biomedical research. Hormonal fluctuations across the menstrual cycle in women has often been cited as a confound by researchers. Attitudes, however, are changing with funding and publication agencies advocating for more inclusive research frameworks and mandating that women and minorities participate in scientific research studies. In this article, we distill the existing knowledge regarding the relationship between light and the menstrual cycle. There is some evidence of a relationship between light and the menstrual cycle, but the nature of this relationship seems dependent on the timing of the light source (sunlight, moonlight, and electric light at night). Light sensitivity may be influenced by biological sex and menstrual phase but there might not be any effect at all. To better understand the relationship between light, the circadian system, and the menstrual cycle, future research needs to be designed thoughtfully, conducted rigorously, and reported transparently.
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Affiliation(s)
- Parisa Vidafar
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Melbourne, VIC, Australia
- Translational Sensory and Circadian Neuroscience, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Manuel Spitschan
- Translational Sensory and Circadian Neuroscience, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- TUM Department of Sport and Health Sciences, Technical University of Munich, Munich, Germany
- TUM Institute for Advanced Study, Technical University of Munich, Garching, Germany
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11
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Brown TM, Brainard GC, Cajochen C, Czeisler CA, Hanifin JP, Lockley SW, Lucas RJ, Münch M, O’Hagan JB, Peirson SN, Price LLA, Roenneberg T, Schlangen LJM, Skene DJ, Spitschan M, Vetter C, Zee PC, Wright KP. Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults. PLoS Biol 2022; 20:e3001571. [PMID: 35298459 PMCID: PMC8929548 DOI: 10.1371/journal.pbio.3001571] [Citation(s) in RCA: 79] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Ocular light exposure has important influences on human health and well-being through modulation of circadian rhythms and sleep, as well as neuroendocrine and cognitive functions. Prevailing patterns of light exposure do not optimally engage these actions for many individuals, but advances in our understanding of the underpinning mechanisms and emerging lighting technologies now present opportunities to adjust lighting to promote optimal physical and mental health and performance. A newly developed, international standard provides a SI-compliant way of quantifying the influence of light on the intrinsically photosensitive, melanopsin-expressing, retinal neurons that mediate these effects. The present report provides recommendations for lighting, based on an expert scientific consensus and expressed in an easily measured quantity (melanopic equivalent daylight illuminance (melaponic EDI)) defined within this standard. The recommendations are supported by detailed analysis of the sensitivity of human circadian, neuroendocrine, and alerting responses to ocular light and provide a straightforward framework to inform lighting design and practice.
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Affiliation(s)
- Timothy M. Brown
- Centre for Biological Timing, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- * E-mail: (TMB); (KPW)
| | - George C. Brainard
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Christian Cajochen
- Centre for Chronobiology, University Psychiatric Clinics Basel, Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
| | - Charles A. Czeisler
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
- Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - John P. Hanifin
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Steven W. Lockley
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
- Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Robert J. Lucas
- Centre for Biological Timing, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Mirjam Münch
- Centre for Chronobiology, University Psychiatric Clinics Basel, Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
- Research Centre for Hauora and Health, Massey University, Wellington, New Zealand
| | - John B. O’Hagan
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, United Kingdom
| | - Stuart N. Peirson
- Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Luke L. A. Price
- Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, United Kingdom
| | - Till Roenneberg
- Institutes for Medical Psychology and Occupational, Social and Environmental Medicine, Medical Faculty, Ludwig-Maximilians University (LMU), Munich, Germany
| | - Luc J. M. Schlangen
- Human Technology Interaction Group, Department of Industrial Engineering and Innovation Sciences, Eindhoven University of Technology, Eindhoven, the Netherlands
- Intelligent Lighting Institute, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Debra J. Skene
- Chronobiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Manuel Spitschan
- Translational Sensory & Circadian Neuroscience, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- TUM Department of Sport and Health Sciences (TUM SG), Technical University of Munich, Munich, Germany
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom
| | - Céline Vetter
- Circadian and Sleep Epidemiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, United States of America
| | - Phyllis C. Zee
- Department of Neurology, Northwestern University, Chicago, Illinois, United States of America
- Center for Circadian and Sleep Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Kenneth P. Wright
- Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, United States of America
- * E-mail: (TMB); (KPW)
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12
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Giménez MC, Stefani O, Cajochen C, Lang D, Deuring G, Schlangen LJM. Predicting melatonin suppression by light in humans: Unifying photoreceptor-based equivalent daylight illuminances, spectral composition, timing and duration of light exposure. J Pineal Res 2022; 72:e12786. [PMID: 34981572 PMCID: PMC9285453 DOI: 10.1111/jpi.12786] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 12/30/2021] [Accepted: 12/30/2021] [Indexed: 12/23/2022]
Abstract
Light-induced melatonin suppression data from 29 peer-reviewed publications was analysed by means of a machine-learning approach to establish which light exposure characteristics (ie photopic illuminance, five α-opic equivalent daylight illuminances [EDIs], duration and timing of the light exposure, and the dichotomous variables pharmacological pupil dilation and narrowband light source) are the main determinants of melatonin suppression. Melatonin suppression in the data set was dominated by four light exposure characteristics: (1) melanopic EDI, (2) light exposure duration, (3) pupil dilation and (4) S-cone-opic EDI. A logistic model was used to evaluate the influence of each of these parameters on the melatonin suppression response. The final logistic model was only based on the first three parameters, since melanopic EDI was the best single (photoreceptor) predictor that was only outperformed by S-cone-opic EDI for (photopic) illuminances below 21 lux. This confirms and extends findings on the importance of the metric melanopic EDI for predicting biological effects of light in integrative (human-centric) lighting applications. The model provides initial and general guidance to lighting practitioners on how to combine spectrum, duration and amount of light exposure when controlling non-visual responses to light, especially melatonin suppression. The model is a starting tool for developing hypotheses on photoreceptors' contributions to light's non-visual responses and helps identifying areas where more data are needed, like on the S-cone contribution at low illuminances.
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Affiliation(s)
- Marina C. Giménez
- Chronobiology UnitGroningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Oliver Stefani
- Centre for Chronobiology and Transfaculty Research Platform Molecular and Cognitive Neurosciences (MCN)Psychiatric Hospital of the University of Basel (UPK) and University of BaselBaselSwitzerland
| | - Christian Cajochen
- Centre for Chronobiology and Transfaculty Research Platform Molecular and Cognitive Neurosciences (MCN)Psychiatric Hospital of the University of Basel (UPK) and University of BaselBaselSwitzerland
| | | | - Gunnar Deuring
- Forensic DepartmentUniversity Psychiatric Clinics BaselBaselSwitzerland
| | - Luc J. M. Schlangen
- Department of Industrial Engineering and Innovation SciencesHuman‐Technology Interaction Group and Intelligent Lighting InstituteEindhoven University of TechnologyEindhovenThe Netherlands
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13
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Van de Putte E, Kindt S, Bracke P, Stevens M, Vansteenkiste M, Vandevivere L, Ryckaert WR. The influence of integrative lighting on sleep and cognitive functioning of shift workers during the morning shift in an assembly plant. APPLIED ERGONOMICS 2022; 99:103618. [PMID: 34775135 DOI: 10.1016/j.apergo.2021.103618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 10/13/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
It is well known that exposure to light at the right time of the day is important to synchronise our circadian rhythm and enhance cognitive functioning. There is, however, a lack of field studies investigating which lighting characteristics are necessary to improve sleep and cognitive functioning. A controlled field study with 80 shift workers was set up, in which the impact of an integrative lighting (IL) scenario was investigated during the morning shift. Two groups were compared: a control group (no change in lighting settings) and a IL-group (exposed to a melanopic Equivalent Daylight Illuminance of 192 lux, i.e., bright light with a high fraction of short-wavelengths). Pre-post measurement of visual comfort, cognitive functioning (D2 task, go-nogo reaction time task) and sleep (MotionWatch8) were performed. The IL-settings ameliorated sleep efficiency and sleep latency during morning shift and enhanced alertness (not inhibition) compared to standard lighting conditions. Changing lighting settings in an industrial setting should be considered as it seems worthwhile for employees' sleep and cognitive performance.
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Affiliation(s)
- Eowyn Van de Putte
- KU Leuven, Department WaveCore/Light and Lighting Laboratory, Ghent, Belgium.
| | - Sara Kindt
- University of Applied Sciences (Howest), Applied Health and Lifestyle Sciences, Bruges, Belgium
| | - Peter Bracke
- KU Leuven, Department WaveCore/Light and Lighting Laboratory, Ghent, Belgium
| | | | - Maarten Vansteenkiste
- Ghent University, Department of Developmental, Personality and Social Psychology, Ghent, Belgium
| | - Lore Vandevivere
- University of Applied Sciences (Howest), Applied Health and Lifestyle Sciences, Bruges, Belgium
| | - Wouter R Ryckaert
- KU Leuven, Department WaveCore/Light and Lighting Laboratory, Ghent, Belgium
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14
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Siraji MA, Kalavally V, Schaefer A, Haque S. Effects of Daytime Electric Light Exposure on Human Alertness and Higher Cognitive Functions: A Systematic Review. Front Psychol 2022; 12:765750. [PMID: 35069337 PMCID: PMC8766646 DOI: 10.3389/fpsyg.2021.765750] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/30/2021] [Indexed: 11/13/2022] Open
Abstract
This paper reports the results of a systematic review conducted on articles examining the effects of daytime electric light exposure on alertness and higher cognitive functions. For this, we selected 59 quantitative research articles from 11 online databases. The review protocol was registered with PROSPERO (CRD42020157603). The results showed that both short-wavelength dominant light exposure and higher intensity white light exposure induced alertness. However, those influences depended on factors like the participants' homeostatic sleep drive and the time of day the participants received the light exposure. The relationship between light exposure and higher cognitive functions was not as straightforward as the alerting effect. The optimal light property for higher cognitive functions was reported dependent on other factors, such as task complexity and properties of control light. Among the studies with short-wavelength dominant light exposure, ten studies (morning: 3; afternoon: 7) reported beneficial effects on simple task performances (reaction time), and four studies (morning: 3; afternoon: 1) on complex task performances. Four studies with higher intensity white light exposure (morning: 3; afternoon: 1) reported beneficial effects on simple task performance and nine studies (morning: 5; afternoon: 4) on complex task performance. Short-wavelength dominant light exposure with higher light intensity induced a beneficial effect on alertness and simple task performances. However, those effects did not hold for complex task performances. The results indicate the need for further studies to understand the influence of short-wavelength dominant light exposure with higher illuminance on alertness and higher cognitive functions.
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Affiliation(s)
- Mushfiqul Anwar Siraji
- Department of Psychology, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Subang Jaya, Malaysia
| | - Vineetha Kalavally
- Department of Electrical and Computer Systems Engineering, School of Engineering, Monash University Malaysia, Subang Jaya, Malaysia
| | - Alexandre Schaefer
- Department of Psychology, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Subang Jaya, Malaysia.,School of Medical and Life Sciences, Sunway University, Subang Jaya, Malaysia
| | - Shamsul Haque
- Department of Psychology, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Subang Jaya, Malaysia
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15
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Fernandez FX. Current Insights into Optimal Lighting for Promoting Sleep and Circadian Health: Brighter Days and the Importance of Sunlight in the Built Environment. Nat Sci Sleep 2022; 14:25-39. [PMID: 35023979 PMCID: PMC8747801 DOI: 10.2147/nss.s251712] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022] Open
Abstract
This perspective considers the possibility that daytime's intrusion into night made possible by electric lighting may not be as pernicious to sleep and circadian health as the encroachment of nighttime into day wrought by 20th century architectural practices that have left many people estranged from sunlight.
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16
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Spitschan M, Santhi N. Individual differences and diversity in human physiological responses to light. EBioMedicine 2022; 75:103640. [PMID: 35027334 PMCID: PMC8808156 DOI: 10.1016/j.ebiom.2021.103640] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 08/18/2021] [Accepted: 10/06/2021] [Indexed: 02/01/2023] Open
Abstract
Exposure to light affects our physiology and behaviour through a pathway connecting the retina to the circadian pacemaker in the hypothalamus - the suprachiasmatic nucleus (SCN). Recent research has identified significant individual differences in the non-visual effects of light,mediated by this pathway. Here, we discuss the fundamentals and individual differences in the non-visual effects of light. We propose a set of actions to improve our evidence database to be more diverse: understanding systematic bias in the evidence base, dedicated efforts to recruit more diverse participants, routine deposition and sharing of data, and development of data standards and reporting guidelines.
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Affiliation(s)
- Manuel Spitschan
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany; Department of Sport and Health Sciences, Technical University of Munich, Munich, Germany; Department of Experimental Psychology, University of Oxford, United Kingdom.
| | - Nayantara Santhi
- Department of Psychology, Northumbria University, United Kingdom.
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17
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Zandi B, Stefani O, Herzog A, Schlangen LJM, Trinh QV, Khanh TQ. Optimising metameric spectra for integrative lighting to modulate the circadian system without affecting visual appearance. Sci Rep 2021; 11:23188. [PMID: 34848762 PMCID: PMC8633386 DOI: 10.1038/s41598-021-02136-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/10/2021] [Indexed: 01/15/2023] Open
Abstract
Smart integrative lighting systems aim to support human health and wellbeing by capitalising on the light-induced effects on circadian rhythms, sleep, and cognitive functions, while optimising the light's visual aspects like colour fidelity, visual comfort, visual preference, and visibility. Metameric spectral tuning could be an instrument to solve potential conflicts between the visual preferences of users with respect to illuminance and chromaticity and the circadian consequences of the light exposure, as metamers can selectively modulate melanopsin-based photoreception without affecting visual properties such as chromaticity or illuminance. This work uses a 6-, 8- and 11-channel LED luminaire with fixed illuminance of 250 lx to systematically investigate the metameric tuning range in melanopic equivalent daylight illuminance (EDI) and melanopic daylight efficacy ratio (melanopic DER) for 561 chromaticity coordinates as optimisation targets (2700 K to 7443 K ± Duv 0 to 0.048), while applying colour fidelity index Rf criteria from the TM-30-20 Annex E recommendations (i.e. Rf [Formula: see text] 85, Rf,h1 [Formula: see text] 85). Our results reveal that the melanopic tuning range increases with rising CCT to a maximum tuning range in melanopic DER of 0.24 (CCT: 6702 K, Duv: 0.003), 0.29 (CCT: 7443 K, Duv: 0) and 0.30 (CCT: 6702, Duv: 0.006), depending on the luminaire's channel number of 6, 8 or 11, respectively. This allows to vary the melanopic EDI from 212.5-227.5 lx up to 275-300 lx without changes in the photopic illuminance (250 lx) or chromaticity ([Formula: see text] [Formula: see text] 0.0014). The highest metameric melanopic Michelson contrast for the 6-, 8- and 11-channel luminaire is 0.16, 0.18 and 0.18, which is accomplished at a CCT of 3017 K (Duv: - 0.018), 3456 K (Duv: 0.009) and 3456 K (Duv: 0.009), respectively. By optimising ~ 490,000 multi-channel LED spectra, we identified chromaticity regions in the CIExy colour space that are of particular interest to control the melanopic efficacy with metameric spectral tuning.
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Affiliation(s)
- Babak Zandi
- Department of Electrical Engineering and Information Technology, Laboratory of Lighting Technology, Technical University of Darmstadt, Darmstadt, Germany.
| | - Oliver Stefani
- Transfaculty Research Platform Molecular and Cognitive Neurosciences (MCN), Centre for Chronobiology, University of Basel, Basel, Switzerland
| | - Alexander Herzog
- Department of Electrical Engineering and Information Technology, Laboratory of Lighting Technology, Technical University of Darmstadt, Darmstadt, Germany
| | - Luc J M Schlangen
- Department Human-Technology, Intelligent Lighting Institute, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Quang Vinh Trinh
- Department of Electrical Engineering and Information Technology, Laboratory of Lighting Technology, Technical University of Darmstadt, Darmstadt, Germany
| | - Tran Quoc Khanh
- Department of Electrical Engineering and Information Technology, Laboratory of Lighting Technology, Technical University of Darmstadt, Darmstadt, Germany
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18
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Elovainio M, Komulainen K, Lipsanen J, Partonen T, Pesonen AK, Pulkki-Råback L, Paunio T, Kähönen M, Vahtera J, Virtanen M, Ruuhela R, Hakulinen C, Raitakari O. Long-term cumulative light exposure from the natural environment and sleep: A cohort study. J Sleep Res 2021; 31:e13511. [PMID: 34729842 DOI: 10.1111/jsr.13511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/18/2021] [Accepted: 10/12/2021] [Indexed: 11/28/2022]
Abstract
We analysed (A) the association of short-term as well as long-term cumulative exposure to natural light, and (B) the association of detailed temporal patterns of natural light exposure history with three indicators of sleep: sleep duration, sleep problems, and diurnal preference. Data (N = 1,962; 55% women; mean age 41.4 years) were from the prospective Young Finns Study, which we linked to daily meteorological data on each participant's neighbourhood natural light exposure using residential postal codes. Sleep outcomes were self-reported in 2011. We first examined associations of the sleep outcomes with cumulative light exposure of 5-year, 2-year, 1-year, and 2-month periods prior to the sleep assessment using linear and Poisson regression models adjusting for potential confounders. We then used a data-driven time series approach to detect clusters of participants with different light exposure histories and assessed the associations of these clusters with the sleep outcomes using linear and Poisson regression analyses. A greater cumulative light exposure over ≥1 year was associated with a shorter sleep duration (β = -0.10, 95% confidence interval [CI] -0.15 to -0.04), more sleep problems (incident rate ratio [IRR] 1.04, 95% CI 1.0-1.07) and diurnal preference towards eveningness (β = -0.09, 95% CI -0.14 to -0.03). The data-driven exposure pattern of "slowly increasing" light exposure was associated with fewer overall sleep problems (IRR 0.93, 95% CI 0.88-0.98) compared to a "recently declining" light exposure group representing the "average-exposure" group. These findings suggest that living in an area with relatively more intense light exposure for a longer period of time influences sleep.
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Affiliation(s)
- Marko Elovainio
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Kaisla Komulainen
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Jari Lipsanen
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Timo Partonen
- Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Anu-Katriina Pesonen
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Laura Pulkki-Råback
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Tiina Paunio
- Department of Psychiatry, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,SleepWell-Research Program, Faculty of Medicine, Helsinki University Hospital, University of Helsinki, Helsinki, Finland
| | - Mikä Kähönen
- Department of Clinical Physiology, Faculty of Medicine and Health Technology, Tampere University Hospital, Tampere University, Tampere, Finland
| | - Jussi Vahtera
- Department of Public Health, University of Turku, Turku, Finland
| | - Marianna Virtanen
- School of Educational Sciences and Psychology, University of Eastern Finland, Joensuu, Finland.,Division of Insurance Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Reija Ruuhela
- Weather and Climate Change Impact Research, Finnish Meteorological Institute, Helsinki, Finland
| | - Christian Hakulinen
- Department of Psychology and Logopedics, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Olli Raitakari
- Centre for Population Health Research, University of Turku, Turku, Finland.,Research Centre of Applied and Preventive Cardiovascular Medicine, Turku University Hospital, University of Turku, Turku, Finland.,Department of Clinical Physiology and Nuclear Medicine, Turku University Hospital, Turku, Finland
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19
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Price LLA, Khazova M, Udovičić L. Assessment of the Light Exposures of Shift-working Nurses in London and Dortmund in Relation to Recommendations for Sleep and Circadian Health. Ann Work Expo Health 2021; 66:447-458. [PMID: 34693970 PMCID: PMC9030150 DOI: 10.1093/annweh/wxab092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 09/22/2021] [Accepted: 10/07/2021] [Indexed: 11/14/2022] Open
Abstract
Shift work causes disruption to circadian physiological processes in the human body, and desynchronization from the natural day-and-night rhythm. Circadian disruption is thought to explain the associations between shift work and various long-term diseases; light is an unrivalled synchronizer (or Zeitgeber) of circadian processes and inappropriate light exposure plausibly plays a critical role in the development of health impairments. As published measurement data on the actual light environments encountered by shift workers are sparse, nurses working in two hospitals in London (UK) and Dortmund (Germany) wore light-logging dosimetry devices to measure personal light exposures continuously over a week in three different seasons. The study identifies and quantifies several of the characteristics of light exposure related to different working patterns in winter, spring, and summer, and quantifies interindividual variations. These data enable informed design of light exposure interventions or changes to shifts to reduce unwanted effects of disruptive light exposure profiles.
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Affiliation(s)
- Luke L A Price
- Radiation Dosimetry Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Harwell Campus, Chilton, Didcot, Oxfordshire, OX11 0RQ, UK
| | - Marina Khazova
- Radiation Dosimetry Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Harwell Campus, Chilton, Didcot, Oxfordshire, OX11 0RQ, UK
| | - Ljiljana Udovičić
- Federal Institute for Occupational Safety and Health (BAuA), Friedrich-Henkel-Weg 1-25, 44149 Dortmund, Germany
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20
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Shahidi R, Golmohammadi R, Babamiri M, Faradmal J, Aliabadi M. Effect of warm/cool white lights on visual perception and mood in warm/cool color environments. EXCLI JOURNAL 2021; 20:1379-1393. [PMID: 34602931 PMCID: PMC8481791 DOI: 10.17179/excli2021-3974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 08/26/2021] [Indexed: 11/10/2022]
Abstract
Color and light are two ambient attributes for interior spaces that can be used in the design and modification of workspaces. The visual and psychological effects of color and light of each have been studied separately and widely. The aim of this study was to investigate the simultaneous effects of warm/cool white light on visual perception and mood in a simulated colored workspace. Thirty-three healthy male participants were recruited. They were asked to judge the visual perception and mood of three types of workspace that were designed by colors of white, red, blue, and lights of a cool and warm white in the random six sessions. The participants have experienced higher levels of tension, anger, depression, anxiety and lower levels of visual comfort, attractiveness, brightness and calmness of environment in the red condition than to white in both state of light. The blue wall reduced brightness and increased attractiveness of environment compared to white wall. Cool white light reduced the warmth of color and increased brightness in all three color environments compared to warm light. The preference for cool or warm light depends on the color of the environment's indoor surface. It seems that the combination of the white color and warm light or the blue color with cool light has a more favorable effect on visual perception and people's mood in workplaces.
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Affiliation(s)
- Reza Shahidi
- Center of Excellence for Occupational Health, School of Public Health and Research Center for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Rostam Golmohammadi
- Center of Excellence for Occupational Health, School of Public Health and Research Center for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mohammad Babamiri
- Social Determinants of Health Research Center, Department of Ergonomics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Javad Faradmal
- Modeling of Noncommunicable Diseases Research Center & Department of Biostatistics and Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mohsen Aliabadi
- Center of Excellence for Occupational Health, Occupational Health and Safety Research Center, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
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21
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Measurement of Circadian Effectiveness in Lighting for Office Applications. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11156936] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
As one factor among others, circadian effectiveness depends on the spatial light distribution of the prevalent lighting conditions. In a typical office context focusing on computer work, the light that is experienced by the office workers is usually composed of a direct component emitted by the room luminaires and the computer monitors as well as by an indirect component reflected from the walls, surfaces, and ceiling. Due to this multi-directional light pattern, spatially resolved light measurements are required for an adequate prediction of non-visual light-induced effects. In this work, we therefore propose a novel methodological framework for spatially resolved light measurements that allows for an estimate of the circadian effectiveness of a lighting situation for variable field of view (FOV) definitions. Results of exemplary in-field office light measurements are reported and compared to those obtained from standard spectral radiometry to validate the accuracy of the proposed approach. The corresponding relative error is found to be of the order of 3–6%, which denotes an acceptable range for most practical applications. In addition, the impact of different FOVs as well as non-zero measurement angles will be investigated.
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22
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Spitschan M. Time-Varying Light Exposure in Chronobiology and Sleep Research Experiments. Front Neurol 2021; 12:654158. [PMID: 34335437 PMCID: PMC8319561 DOI: 10.3389/fneur.2021.654158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 05/06/2021] [Indexed: 12/17/2022] Open
Abstract
Light exposure profoundly affects human physiology and behavior through circadian and neuroendocrine photoreception primarily through the melanopsin-containing intrinsically photosensitive retinal ganglion cells. Recent research has explored the possibility of using temporally patterned stimuli to manipulate circadian and neuroendocrine responses to light. This mini-review, geared to chronobiologists, sleep researchers, and scientists in adjacent disciplines, has two objectives: (1) introduce basic concepts in time-varying stimuli and (2) provide a checklist-based set of recommendations for documenting time-varying light exposures based on current best practices and standards.
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Affiliation(s)
- Manuel Spitschan
- Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom.,Centre for Chronobiology, Psychiatric Hospital of the University of Basel (UPK), Basel, Switzerland.,Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
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23
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Papatsimpa C, Schlangen LJM, Smolders KCHJ, Linnartz JPMG, de Kort YAW. The interindividual variability of sleep timing and circadian phase in humans is influenced by daytime and evening light conditions. Sci Rep 2021; 11:13709. [PMID: 34211005 PMCID: PMC8249410 DOI: 10.1038/s41598-021-92863-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 06/17/2021] [Indexed: 02/06/2023] Open
Abstract
Human cognitive functioning shows circadian variations throughout the day. However, individuals largely differ in their timing during the day of when they are more capable of performing specific tasks and when they prefer to sleep. These interindividual differences in preferred temporal organization of sleep and daytime activities define the chronotype. Since a late chronotype is associated with adverse mental and physical consequences, it is of vital importance to study how lighting environments affect chronotype. Here, we use a mathematical model of the human circadian pacemaker to understand how light in the built environment changes the chronotype distribution in the population. In line with experimental findings, we show that when individuals spend their days in relatively dim light conditions, this not only results in a later phase of their biological clock but also increases interindividual differences in circadian phase angle of entrainment and preferred sleep timing. Increasing daytime illuminance results in a more narrow distribution of sleep timing and circadian phase, and this effect is more pronounced for longer photoperiods. The model results demonstrate that modern lifestyle changes the chronotype distribution towards more eveningness and more extreme differences in eveningness. Such model-based predictions can be used to design guidelines for workplace lighting that help limiting circadian phase differences, and craft new lighting strategies that support human performance, health and wellbeing.
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Affiliation(s)
- C. Papatsimpa
- grid.6852.90000 0004 0398 8763Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - L. J. M. Schlangen
- grid.6852.90000 0004 0398 8763Department of Industrial Engineering and Innovation Sciences, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - K. C. H. J. Smolders
- grid.6852.90000 0004 0398 8763Department of Industrial Engineering and Innovation Sciences, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - J.-P. M. G. Linnartz
- grid.6852.90000 0004 0398 8763Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands ,grid.510043.3Signify, Eindhoven, The Netherlands
| | - Y. A. W. de Kort
- grid.6852.90000 0004 0398 8763Department of Industrial Engineering and Innovation Sciences, Eindhoven University of Technology, Eindhoven, The Netherlands
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24
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Standardizing Melanopic Effects of Ocular Light for Ecological Lighting Design of Nonresidential Buildings—An Overview of Current Legislation and Accompanying Scientific Studies. SUSTAINABILITY 2021. [DOI: 10.3390/su13095131] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
DIN SPEC 5031-100 and CIE S 026:2018 are regulatory frameworks that are intended to establish health-preserving indoor lighting in Europe. Therefore, they are crucial for the visual environment and its sustainability. The standards are largely congruent. Inconsistencies should now be harmonized with the newly published draft standard DIN/TS 5031-100, for which the objection period ended on 3 June 2020; thus, it can be expected that the standard will soon be put into operation. This publication provides the reader with a detailed technical as well as medical overview of the scope and background information on how the standard came about. Applicable laws, ordinances and standards were compiled across countries, and related studies were reviewed. It is demonstrated that the focus of this new standard, as with previous versions, is on the melanopic sensitivity of ganglion cells. The authors base this on a literature search for projects about ecological lighting design over the past 20 years. However, in practice, the publication of the standard does not yet completely counteract the health effects of inappropriate indoor lighting.
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