1
|
Yoon J, Heo SJ, Lee H, Sul EG, Han T, Kwon YJ. Assessing the Feasibility and Efficacy of Pre-Sleep Dim Light Therapy for Adults with Insomnia: A Pilot Study. MEDICINA (KAUNAS, LITHUANIA) 2024; 60:632. [PMID: 38674278 PMCID: PMC11052339 DOI: 10.3390/medicina60040632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/09/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024]
Abstract
Background: Insomnia is increasingly recognized for its marked impact on public health and is often associated with various adverse health outcomes, including cardiovascular diseases and mental health disorders. The aim of this study was to investigate the efficacy of pre-sleep dim light therapy (LT) as a non-pharmacological intervention for insomnia in adults, assessing its influence on sleep parameters and circadian rhythms. Methods: A randomized, open-label, two-arm clinical trial was conducted over two weeks with 40 participants aged 20-60 years, all of whom had sleep disorders (CRIS, KCT0008501). They were allocated into control and LT groups. The LT group received exposure to warm-colored light, minimizing the blue spectrum, before bedtime. The study combined subjective evaluation via validated, sleep-related questionnaires, objective sleep assessments via actigraphy, and molecular analyses of circadian clock gene expression in peripheral blood mononuclear cells. Baseline characteristics between the two groups were compared using an independent t-test for continuous variables and the chi-squared test for categorical variables. Within-group differences were assessed using the paired t-test. Changes between groups were analyzed using linear regression, adjusting for each baseline value and body mass index. The patterns of changes in sleep parameters were calculated using a linear mixed model. Results: The LT group exhibited significant improvements in sleep quality (difference in difference [95% CI]; -2.00 [-3.58, -0.43], and sleep efficiency (LT: 84.98 vs. control: 82.11, p = 0.032), and an advanced Dim Light Melatonin Onset compared to the control group (approximately 30 min). Molecular analysis indicated a significant reduction in CRY1 gene expression after LT, suggesting an influence on circadian signals for sleep regulation. Conclusions: This study provides evidence for the efficacy of LT in improving sleep quality and circadian rhythm alignment in adults with insomnia. Despite limitations, such as a small sample size and short study duration, the results underscore the potential of LT as a viable non-pharmacological approach for insomnia. Future research should expand on these results with larger and more diverse cohorts followed over a longer period to validate and further elucidate the value of LT in sleep medicine. Trial registration: The trial was registered with the Clinical Research Information Service (KCT0008501).
Collapse
Affiliation(s)
- Jihyun Yoon
- Department of Family Medicine, Anam Hospital, Korea University College of Medicine, Seoul 02481, Republic of Korea;
| | - Seok-Jae Heo
- Division of Biostatistics, Department of Biomedical Systems Informatics, Yonsei University College of Medicine, Seoul 03722, Republic of Korea;
| | - Hyangkyu Lee
- College of Nursing, Mo-Im Kim Research Institute, Yonsei University, Seoul 03722, Republic of Korea;
| | - Eun-Gyeong Sul
- Department of Family Medicine, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin 16995, Republic of Korea;
| | - Taehwa Han
- Integrative Research Center for Cerebrovascular and Cardiovascular Diseases, Yonsei University College of Medicine, Seoul 03722, Republic of Korea
| | - Yu-Jin Kwon
- Department of Family Medicine, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin 16995, Republic of Korea;
| |
Collapse
|
2
|
Sweeney MR, Nichols HB, Jones RR, Olshan AF, Keil AP, Engel LS, James P, Sandler DP, White AJ, Jackson CL. Exposure to indoor light at night in relation to multiple dimensions of sleep health: findings from the Sister Study. Sleep 2024; 47:zsad100. [PMID: 37018759 PMCID: PMC10851850 DOI: 10.1093/sleep/zsad100] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 02/23/2023] [Indexed: 04/07/2023] Open
Abstract
STUDY OBJECTIVE To examine the association between light at night (LAN) and multiple sleep health dimensions. METHODS Among 47 765 Sister Study participants, indoor LAN (TV on in the room, light(s) on in room, light from outside the room, nightlight, no light) and sleep dimensions were self-reported at baseline (2003-2009). We used Poisson regression with robust variance to estimate adjusted prevalence ratios (PR) and 95% confidence intervals (CI) for the cross-sectional associations between LAN and short sleep duration (<7 hours/night), insomnia symptoms (difficulty falling or staying asleep), frequent napping (≥3 naps/week), inconsistent sleep/wake time (differed day-to-day and week-to-week), sleep debt (≥2 hours between longest and shortest duration), recent sleep medication use, and a cumulative poor sleep score (≥3 poor sleep dimensions). Population-attributable risks (PARs) were determined for any light exposure vs. none by race/ethnicity. RESULTS Compared to sleeping with no light in the bedroom, sleeping with a TV on was associated with a higher prevalence of most dimensions of poor sleep (e.g. short sleep duration: PR = 1.38, 95% CI: 1.32 to 1.45; inconsistent sleep/wake time: PR = 1.55, 95% CI: 1.44 to 1.66; sleep debt: PR = 1.36, 95% CI: 1.29 to 1.44; poor sleep score: PR = 1.58, 95% CI: 1.48-1.68). PARs tended to be higher for non-Hispanic black women compared to non-Hispanic white women. CONCLUSIONS Sleeping with a TV on was associated with poor sleep health among US women, and non-Hispanic black women may be disproportionately burdened.
Collapse
Affiliation(s)
- Marina R Sweeney
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
- Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Hazel B Nichols
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Rena R Jones
- Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD, USA
| | - Andrew F Olshan
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Alexander P Keil
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Lawrence S Engel
- Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, NC, USA
| | - Peter James
- Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA, USA
- Department of Environmental Health, Harvard TH Chan School of Public Health, Boston, MA, USA
| | - Dale P Sandler
- Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Alexandra J White
- Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
| | - Chandra L Jackson
- Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
- Division of Intramural Research, National Institute on Minority Health and Health Disparities, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA
| |
Collapse
|
3
|
Johnson DA, Wallace DA, Ward L. Racial/ethnic and sex differences in the association between light at night and actigraphy-measured sleep duration in adults: NHANES 2011-2014. Sleep Health 2024; 10:S184-S190. [PMID: 37951773 PMCID: PMC11031299 DOI: 10.1016/j.sleh.2023.09.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 09/18/2023] [Accepted: 09/22/2023] [Indexed: 11/14/2023]
Abstract
OBJECTIVE Historically minoritized individuals experience greater exposure to light at night, yet it is unclear whether the association between light at night and sleep duration vary by race/ethnicity or sex. We examined the association between light at night and sleep duration by race/ethnicity and sex. METHODS Participants (N = 6089, mean age=49.5, 52% women, 13% Asian, 27% Black, 14% Mexican, 46% White) in the 2011-2014 National Health and Nutrition Examination Survey underwent 9-day of actigraphy. Light at night was defined as light exposure within the 5-hour activity nadir (L5). Sleep duration within a 24-hour period was analyzed as short (<7 hours) or long (>9 hours) compared to recommended (≥7 and <9 hours). Poisson models were fit to estimate the association between light at night and sleep duration after adjustment for covariates. RESULTS Light at night was most common among Black participants, who also had the shortest sleep duration. Overall, light at night was associated with 80% higher prevalence of short sleep duration [1.80 (1.49, 2.18)]. Compared to no-light at night, low and high light at night were associated with higher prevalence of short sleep duration, [1.61 (1.31, 1.98) and 2.01 (1.66, 2.44), respectively]. Associations varied by race/ethnicity and sex. Light at night was associated with shorter sleep duration in Black, Mexican and White females and Mexican and White males only. Black males exposed to light at night vs. no-light at night had lower prevalence of long sleep duration. There were no associations between light at night and sleep duration among Asian participants. CONCLUSION Light at night was associated with shorter sleep duration, particularly among females. Targeting light exposure may help to improve sleep duration.
Collapse
Affiliation(s)
- Dayna A Johnson
- Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA.
| | - Danielle A Wallace
- Department of Medicine, Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA; Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Laura Ward
- Department of Biostatistics and Informatics, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
| |
Collapse
|
4
|
Klerman EB, Wright KP, Duffy JF, Scheer FAJL, Chang AM, Czeisler CA, Rajaratnam SM. A perspective on the Festschrift of Charles A. Czeisler, PhD MD. Sleep Health 2024; 10:S4-S10. [PMID: 38331654 PMCID: PMC11031332 DOI: 10.1016/j.sleh.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Affiliation(s)
- Elizabeth B Klerman
- Department of Neurology, Massachusetts General Hospital, Boston, USA; Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA; Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA.
| | - Kenneth P Wright
- Sleep and Chronobiology Laboratory, Department of Integrative Physiology., University of Colorado Boulder, USA
| | - Jeanne F Duffy
- Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA; Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Frank A J L Scheer
- Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA; Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Anne-Marie Chang
- Department of Biobehavioral Health, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Charles A Czeisler
- Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA; Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Shantha Mw Rajaratnam
- Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA; Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA; School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Victoria, Australia
| |
Collapse
|
5
|
Ajayi OM, Wynne NE, Chen SC, Vinauger C, Benoit JB. Sleep: An Essential and Understudied Process in the Biology of Blood-Feeding Arthropods. Integr Comp Biol 2023; 63:530-547. [PMID: 37429615 PMCID: PMC10503478 DOI: 10.1093/icb/icad097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 07/01/2023] [Accepted: 07/03/2023] [Indexed: 07/12/2023] Open
Abstract
Understanding the biology of blood-feeding arthropods is critical to managing them as vectors of etiological agents. Circadian rhythms act in the regulation of behavioral and physiological aspects such as blood feeding, immunity, and reproduction. However, the impact of sleep on these processes has been largely ignored in blood-feeding arthropods, but recent studies in mosquitoes show that sleep-like states directly impact host landing and blood feeding. Our focus in this review is on discussing the relationship between sleep and circadian rhythms in blood-feeding arthropods along with how unique aspects such as blood gluttony and dormancy can impact sleep-like states. We highlight that sleep-like states are likely to have profound impacts on vector-host interactions but will vary between lineages even though few direct studies have been conducted. A myriad of factors, such as artificial light, could directly impact the time and levels of sleep in blood-feeding arthropods and their roles as vectors. Lastly, we discuss underlying factors that make sleep studies in blood-feeding arthropods difficult and how these can be bypassed. As sleep is a critical factor in the fitness of animal systems, a lack of focus on sleep in blood-feeding arthropods represents a significant oversight in understanding their behavior and its role in pathogen transmission.
Collapse
Affiliation(s)
- Oluwaseun M Ajayi
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Nicole E Wynne
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Shyh-Chi Chen
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Clément Vinauger
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
| | - Joshua B Benoit
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| |
Collapse
|
6
|
Canazei M, Dick M, Pohl W, Weninger J, Hubel N, Staggl S, Weiss EM. Impact of repeated morning bright white light exposures on attention in a simulated office environment. Sci Rep 2023; 13:8730. [PMID: 37253767 DOI: 10.1038/s41598-023-35689-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 05/22/2023] [Indexed: 06/01/2023] Open
Abstract
Attention is essential to the work. This study investigated the effects of two different light pulses on a simple attention task. In addition, the effects of subsequent exposure to constant but different illuminance levels on the continuation of the simple attention task and a subsequent complex attention task were examined. A total of 56 subjects were assigned in random order to two white light interventions that were repeated five times during the morning. Each light intervention consisted of a brief light pulse followed by constant light exposure and differed in temporal dimming dynamics and corneal illuminance. Subjective and psychometric parameters were recorded several times during light exposure. Heart rate variability (HRV) was derived from continuous electrocardiograms. Subjects showed improved reaction speed in the simple attention task, accompanied by higher HRV under a brighter light pulse without habituation by repetition. This difference in simple attention performance disappeared when light exposure remained the same after the light pulse. In addition, higher reaction speed and HRV were observed in the complex attention task under constant bright light exposure. Intermittent bright light seems promising to acutely improve attentional performance in office workplaces. Future research is needed to investigate daytime light effects on other work-related cognitive functions.
Collapse
Affiliation(s)
- Markus Canazei
- Department of Psychology, University of Innsbruck, Innrain 52 F, 6020, Innsbruck, Austria.
| | - Maximilian Dick
- Department of Psychology, University of Innsbruck, Innrain 52 F, 6020, Innsbruck, Austria
- Research and Development Department, Bartenbach GmbH, Rinnerstrasse 14, Aldrans, Austria
| | - Wilfried Pohl
- Research and Development Department, Bartenbach GmbH, Rinnerstrasse 14, Aldrans, Austria
| | - Johannes Weninger
- Research and Development Department, Bartenbach GmbH, Rinnerstrasse 14, Aldrans, Austria
| | - Niclas Hubel
- Department of Psychology, University of Innsbruck, Innrain 52 F, 6020, Innsbruck, Austria
| | - Siegmund Staggl
- Department of Psychology, University of Innsbruck, Innrain 52 F, 6020, Innsbruck, Austria
| | - Elisabeth M Weiss
- Department of Psychology, University of Innsbruck, Innrain 52 F, 6020, Innsbruck, Austria
| |
Collapse
|
7
|
Hartstein LE, Behn CD, Wright KP, Akacem LD, Stowe SR, LeBourgeois MK. Evening Light Intensity and Phase Delay of the Circadian Clock in Early Childhood. J Biol Rhythms 2023; 38:77-86. [PMID: 36415902 PMCID: PMC11302507 DOI: 10.1177/07487304221134330] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Late sleep timing is prevalent in early childhood and a risk factor for poor behavioral and health outcomes. Sleep timing is influenced by the phase of the circadian clock, with later circadian timing linked to delayed sleep onset in young children. Light is the strongest zeitgeber of circadian timing and, in adults, evening light produces circadian phase delay in an intensity-dependent manner. The intensity-dependent circadian phase-shifting response to evening light in children, however, is currently unknown. In the present study, 33 healthy, good-sleeping children aged 3.0 to 4.9 years (M = 4.14 years, 39% male) completed a 10-day between-subjects protocol. Following 7 days of a stable sleep schedule, an in-home dim-light circadian assessment was performed. Children remained in dim-light across 3 days (55 h), with salivary melatonin collected in regular intervals throughout each evening. Phase-shifting effects of light exposure were determined via changes in the timing of the dim-light melatonin onset (DLMO) prior to (Day 8) and following (Day 10) a light exposure stimulus. On Day 9, children were exposed to a 1 h light stimulus in the hour before their habitual bedtime. Each child was randomly assigned to one intensity between 5 and 5000 lux (4.5-3276 melanopic EDI). Across light intensities, children showed significant circadian phase delays, with an average phase delay of 56.1 min (SD = 33.6 min), and large inter-individual variability. No relationship between light intensity and magnitude of the phase shift was observed. However, a greater percentage of melatonin suppression during the light exposure was associated with a greater phase delay (r = -0.73, p < 0.01). These findings demonstrate that some young children may be highly sensitive to light exposure in the hour before bedtime and suggest that the home lighting environment and its impact on circadian timing should be considered a possible contributor to behavioral sleep difficulties.
Collapse
Affiliation(s)
- Lauren E. Hartstein
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Cecilia Diniz Behn
- Department of Applied Mathematics and Statistics, Colorado School of Mines, Golden, CO, USA
- Division of Endocrinology, Department of Pediatrics, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
| | - Kenneth P. Wright
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Lameese D. Akacem
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, Rockville, MD, USA
| | - Shelby R. Stowe
- Department of Applied Mathematics and Statistics, Colorado School of Mines, Golden, CO, USA
| | | |
Collapse
|
8
|
Yousefzadehfard Y, Wechsler B, DeLorenzo C. Human circadian rhythm studies: Practical guidelines for inclusion/exclusion criteria and protocol. Neurobiol Sleep Circadian Rhythms 2022; 13:100080. [PMID: 35989718 PMCID: PMC9382328 DOI: 10.1016/j.nbscr.2022.100080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 08/01/2022] [Accepted: 08/02/2022] [Indexed: 11/03/2022] Open
Abstract
As interest in circadian rhythms and their effects continues to grow, there is an increasing need to perform circadian studies in humans. Although the constant routine is the gold standard for these studies, there are advantages to performing more naturalistic studies. Here, a review of protocols for such studies is provided along with sample inclusion and exclusion criteria. Sleep routines, drug use, shift work, and menstrual cycle are addressed as screening considerations. Regarding protocol, best practices for measuring melatonin, including light settings, posture, exercise, and dietary habits are described. The inclusion/exclusion recommendations and protocol guidelines are intended to reduce confounding variables in studies that do not involve the constant routine. Given practical limitations, a range of recommendations is provided from stringent to lenient. The scientific rationale behind these recommendations is discussed. However, where the science is equivocal, recommendations are based on empirical decisions made in previous studies. While not all of the recommendations listed may be practical in all research settings and with limited potential participants, the goal is to allow investigators to make well informed decisions about their screening procedures and protocol techniques and to improve rigor and reproducibility, in line with the objectives of the National Institutes of Health.
Collapse
Affiliation(s)
- Yashar Yousefzadehfard
- Center for Understanding Biology Using Imaging Technology, Department of Psychiatry, Stony Brook University, Stony Brook, NY, USA.,Department of Psychiatry, Texas Tech University Health Science Center, Midland, TX, USA
| | - Bennett Wechsler
- Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA, USA
| | - Christine DeLorenzo
- Center for Understanding Biology Using Imaging Technology, Department of Psychiatry, Stony Brook University, Stony Brook, NY, USA
| |
Collapse
|
9
|
Hu K, Li W, Zhang Y, Chen H, Bai C, Yang Z, Lorenz T, Liu K, Shirai K, Song J, Zhao Q, Zhao Y, Zhang JJ, Wei J, Pan J, Qi J, Ye T, Zeng Y, Yao Y. Association between outdoor artificial light at night and sleep duration among older adults in China: A cross-sectional study. ENVIRONMENTAL RESEARCH 2022; 212:113343. [PMID: 35461841 DOI: 10.1016/j.envres.2022.113343] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 04/14/2022] [Accepted: 04/18/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Light after dusk disrupts the circadian rhythms and shifts the timing of sleep later; but it is unknown whether outdoor artificial light at night (ALAN) affects sleep quality. This study aimed to explore the association between residential outdoor ALAN and sleep duration in a nationally representative sample of Chinese older adults. METHODS We examined the cross-sectional associations of outdoor ALAN with self-reported sleep duration in 13,474 older adults participating in the 2017-2018 wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Outdoor ALAN exposure was estimated at the residence level using satellite images. We applied generalized linear mixed models to investigate the association between ALAN exposure and sleep duration. We performed stratified analyses by age, sex, education, and household income levels. Moreover, we used multi-level logistic regression models to investigate the effects of ALAN on the short sleep duration (≤6 h) and the long sleep duration (>8 h), respectively, in reference to sleep for >6-8 h per day. RESULTS We found a significant association between outdoor ALAN intensity and sleep duration. The highest quartile of ALAN was associated with 17.04 (95% CI: 9.42-24.78) fewer minutes of sleep as compared to the lowest quartile. The reductions in sleep duration per quartile change in ALAN were greater in the young old (≥65-85 years) and in those with higher levels of education, and those with higher household income, respectively. We did not detect a sex difference. In addition, those in the highest quartile of ALAN were more likely to report a 25% (95% CI: 10%-42%) increase in short sleep (<6 h), and a 21% (95% CI: 9%-31%) decrease in long sleep (>8 h). CONCLUSIONS Increasing outdoor nighttime light intensity surrounding residences was associated with shorter sleep duration in older residents in China. This finding implies the importance of urban outdoor artificial light management as a potential means to lower the public health burden of sleep disorders.
Collapse
Affiliation(s)
- Kejia Hu
- Department of Big Data in Health Science, School of Public Health, Zhejiang University, Hangzhou, 310058, China
| | - Wanlu Li
- Department of Big Data in Health Science, School of Public Health, Zhejiang University, Hangzhou, 310058, China
| | - Yunquan Zhang
- School of Public Health, Wuhan University of Science and Technology, Wuhan, 430065, China
| | - Huashuai Chen
- Business School of Xiangtan University, Xiangtan, 411105, China
| | - Chen Bai
- School of Labor and Human Resources, Renmin University of China, Beijing, 100872, China
| | - Zhenchun Yang
- Global Health Institute and the Nicholas School of Environment, Duke University, Durham, 27708, USA
| | - Thiess Lorenz
- Department of Cardiology, University Heart and Vascular Center Hamburg, Hamburg, 20246, Germany
| | - Keyang Liu
- Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, Suita Shi, Osaka, 565-0871, Japan
| | - Kokoro Shirai
- Public Health, Department of Social Medicine, Osaka University Graduate School of Medicine, Suita Shi, Osaka, 565-0871, Japan
| | - Jinglu Song
- Department of Urban Planning and Design, Xi'an Jiaotong-Liverpool University, Suzhou, 215123, China
| | - Qi Zhao
- Department of Epidemiology, School of Public Health, Shandong University, Jinan, 250012, China
| | - Yali Zhao
- Central Laboratory, Hainan Hospital of Chinese People's Liberation Army General Hospital, Sanya, 572000, China
| | - Junfeng Jim Zhang
- Global Health Institute and the Nicholas School of Environment, Duke University, Durham, 27708, USA
| | - Jing Wei
- Department of Atmospheric and Oceanic Science, Earth System Science Interdisciplinary Center, University of Maryland, College Park, 20742, USA
| | - Jiahao Pan
- Department of Big Data in Health Science, School of Public Health, Zhejiang University, Hangzhou, 310058, China
| | - Jin Qi
- Department of Big Data in Health Science, School of Public Health, Zhejiang University, Hangzhou, 310058, China
| | - Tingting Ye
- School of Public Health and Preventive Medicine, Monash University, Melbourne, 3004, Australia
| | - Yi Zeng
- Center for Healthy Aging and Development Studies, National School of Development, Peking University, Beijing, 100871, China.
| | - Yao Yao
- China Center for Health Development Studies, Peking University, Beijing, 100191, China.
| |
Collapse
|
10
|
Rahman SA, St. Hilaire MA, Grant LK, Barger LK, Brainard GC, Czeisler CA, Klerman EB, Lockley SW. Dynamic lighting schedules to facilitate circadian adaptation to shifted timing of sleep and wake. J Pineal Res 2022; 73:e12805. [PMID: 35501292 PMCID: PMC11316502 DOI: 10.1111/jpi.12805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/21/2022] [Accepted: 05/01/2022] [Indexed: 11/28/2022]
Abstract
Circadian adaptation to shifted sleep/wake schedules may be facilitated by optimizing the timing, intensity and spectral characteristics of light exposure, which is the principal time cue for mammalian circadian pacemaker, and possibly by strategically timing nonphotic time cues such as exercise. Therefore, circadian phase resetting by light and exercise was assessed in 44 healthy participants (22 females, mean age [±SD] 36.2 ± 9.2 years), who completed 8-day inpatient experiments simulating night shiftwork, which included either an 8 h advance or 8 h delay in sleep/wake schedules. In the advance protocol (n = 18), schedules were shifted either gradually (1.6 h/day across 5 days) or abruptly (slam shift, 8 h in 1 day and maintained across 5 days). Both advance protocols included a dynamic lighting schedule (DLS) with 6.5 h exposure of blue-enriched white light (704 melanopic equivalent daylight illuminance [melEDI] lux) during the day and dimmer blue-depleted light (26 melEDI lux) for 2 h immediately before sleep on the shifted schedule. In the delay protocol (n = 26), schedules were only abruptly delayed but included four different lighting conditions: (1) 8 h continuous room-light control; (2) 8 h continuous blue-enriched light; (3) intermittent (7 × 15 min pulses/8 h) blue-enriched light; (4) 8 h continuous blue-enriched light plus moderate intensity exercise. In the room-light control, participants received dimmer white light for 30 min before bedtime, whereas in the other three delay protocols participants received dimmer blue-depleted light for 30 min before bedtime. Both the slam and gradual advance protocols induced similar shifts in circadian phase (3.28 h ± 0.37 vs. 2.88 h ± 0.31, respectively, p = .43) estimated by the change in the timing of timing of dim light melatonin onset. In the delay protocol, the continuous 8 h blue-enriched exposure induced significantly larger shifts than the room light control (-6.59 h ± 0.43 vs. -4.74 h ± 0.62, respectively, p = .02). The intermittent exposure induced ~60% of the shift (-3.90 h ± 0.62) compared with 8 h blue-enriched continuous light with only 25% of the exposure duration. The addition of exercise to the 8 h continuous blue-enriched light did not result in significantly larger phase shifts (-6.59 h ± 0.43 vs. -6.41 h ± 0.69, p = .80). Collectively, our results demonstrate that, when attempting to adapt to an 8 h overnight work shift, delay shifts are more successful, particularly when accompanied by a DLS with high-melanopic irradiance light stimulus during wake.
Collapse
Affiliation(s)
- Shadab A. Rahman
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA
| | - Melissa A. St. Hilaire
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA
| | - Leilah K. Grant
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA
| | - Laura K. Barger
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA
| | - George C. Brainard
- Light Research Program, Department of Neurology, Thomas Jefferson University, Philadelphia, PA
| | - Charles A. Czeisler
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA
| | - Elizabeth B. Klerman
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA
- Department of Neurology, Massachusetts General Hospital, Boston, MA
| | - Steven W. Lockley
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA
| |
Collapse
|
11
|
ICU Patients’ Perception of Sleep and Modifiable versus Non-Modifiable Factors That Affect It: A Prospective Observational Study. J Clin Med 2022; 11:jcm11133725. [PMID: 35807010 PMCID: PMC9267898 DOI: 10.3390/jcm11133725] [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: 05/23/2022] [Revised: 06/17/2022] [Accepted: 06/24/2022] [Indexed: 11/17/2022] Open
Abstract
Background: Good sleep quantity and quality are essential for patient recovery while in the intensive care unit (ICU). Patients commonly report poor sleep while in the ICU, and therefore, identifying the modifiable factors that patients perceive as impacting their sleep is important to improve sleep and recovery. This study also assessed night-time light and sound levels in an ICU in an effort to find modifiable factors. Methods: A total of 137 patients (51F) aged 58.1 ± 16.8 years completed a survey including questions about their sleep before and during their ICU stay, factors contributing to poor sleep in the ICU, and perceived factors that may have improved their sleep in the ICU. Night-time light and sound levels were measured in patient rooms and nurses’ stations. Results: Patients reported poorer sleep quantity and quality while in the ICU compared to home. Among the most common reasons for poor sleep, easily modifiable factors included noise (50.4%) and lights (45.3%), potentially modifiable factors included pain (46.7%), and non-modifiable factors included IV lines (42.3%). Patients felt their sleep would have been improved with interventions such as dimming lights (58.4%) and closing doors/blinds at night (42.3%), as well as potentially implementable interventions such as a sleeping pill (51.8%). Overnight sound levels in bedrooms were above the recommended levels (40 dB) and light levels averaged over 100 lux. Conclusions: Sleep quality and quantity were both worse in ICU than at home. Modifiable factors such as sound and light are common factors that patients perceive impact their sleep in the ICU. Readily implementable sleep management strategies aimed at minimizing the impacts of sound and light levels in the ICU are ways to improve patients’ sleep in the ICU.
Collapse
|
12
|
Benedetti M, Maierová L, Cajochen C, Scartezzini JL, Münch M. Optimized office lighting advances melatonin phase and peripheral heat loss prior bedtime. Sci Rep 2022; 12:4267. [PMID: 35277539 PMCID: PMC8917232 DOI: 10.1038/s41598-022-07522-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 02/16/2022] [Indexed: 12/05/2022] Open
Abstract
Improving indoor lighting conditions at the workplace has the potential to support proper circadian entrainment of hormonal rhythms, sleep, and well-being. We tested the effects of optimized dynamic daylight and electric lighting on circadian phase of melatonin, cortisol and skin temperatures in office workers. We equipped one office room with an automated controller for blinds and electric lighting, optimized for dynamic lighting (= Test room), and a second room without any automated control (= Reference room). Young healthy participants (n = 34) spent five consecutive workdays in each room, where individual light exposure data, skin temperatures and saliva samples for melatonin and cortisol assessments were collected. Vertical illuminance in the Test room was 1177 ± 562 photopic lux (mean ± SD) , which was 320 lux higher than in the Reference room (p < 0.01). Melanopic equivalent daylight (D65) illuminance was 931 ± 484 melanopic lux in the Test room and 730 ± 390 melanopic lux in the Reference room (p < 0.01). Individual light exposures resulted in a 50 min earlier time of half-maximum accumulated illuminance in the Test than the Reference room (p < 0.05). The melatonin secretion onset and peripheral heat loss in the evening occurred significantly earlier with respect to habitual sleeptime in the Test compared to the Reference room (p < 0.05). Our findings suggest that optimized dynamic workplace lighting has the potential to promote earlier melatonin onset and peripheral heat loss prior bedtime, which may be beneficial for persons with a delayed circadian timing system.
Collapse
Affiliation(s)
- Marta Benedetti
- Solar Energy and Building Physics Laboratory (LESO-PB), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland.
| | - Lenka Maierová
- University Centre for Energy Efficient Buildings (UCEEB), Czech Technical University in Prague, Trinecka 1024, 27343, Bustehrad, Czech Republic
| | - Christian Cajochen
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Wilhelm Klein-Strasse 27, 4002, Basel, Switzerland
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland
| | - Jean-Louis Scartezzini
- Solar Energy and Building Physics Laboratory (LESO-PB), Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Mirjam Münch
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Wilhelm Klein-Strasse 27, 4002, Basel, Switzerland.
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, Basel, Switzerland.
- Research Centre for Hauora and Health, Massey University, Wellington, New Zealand.
| |
Collapse
|
13
|
Joyce DS, Spitschan M, Zeitzer JM. Duration invariance and intensity dependence of the human circadian system phase shifting response to brief light flashes. Proc Biol Sci 2022; 289:20211943. [PMID: 35259981 PMCID: PMC8905166 DOI: 10.1098/rspb.2021.1943] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 02/14/2022] [Indexed: 01/09/2023] Open
Abstract
The melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs) are characterized by a delayed off-time following the cessation of light stimulation. Here, we exploited this unusual physiologic property to characterize the exquisite sensitivity of the human circadian system to flashed light. In a 34 h in-laboratory between-subjects design, we examined phase shifting in response to variable-intensity (3-9500 photopic lux) flashes at fixed duration (2 ms; n = 28 participants) and variable-duration (10 µs-10 s) flashes at fixed intensity (2000 photopic lux; n = 31 participants). Acute melatonin suppression, objective alertness and subjective sleepiness during the flash sequence were also assessed. We find a dose-response relationship between flash intensity and circadian phase shift, with an indication of a possible threshold-like behaviour. We find a slight parametric relationship between flash duration and circadian phase shift. Consistent with prior studies, we observe no dose-response relationship to either flash intensity or duration and the acute impact of light on melatonin suppression, objective alertness or subjective sleepiness. Our findings are consistent with circadian responses to a sequence of flashes being mediated by rod or cone photoreceptors via ipRGC integration.
Collapse
Affiliation(s)
- Daniel S. Joyce
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Mental Illness Research Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA, USA
- Department of Psychology, University of Nevada Reno, Reno, NV, USA
| | - Manuel Spitschan
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Translational Sensory and 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
| | - Jamie M. Zeitzer
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Mental Illness Research Education and Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA, USA
| |
Collapse
|
14
|
Kaladchibachi S, Negelspach DC, Zeitzer JM, Fernandez FX. Investigation of the aging clock's intermittent-light responses uncovers selective deficits to green millisecond flashes. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2022; 228:112389. [PMID: 35086027 DOI: 10.1016/j.jphotobiol.2022.112389] [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: 07/31/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
The central pacemaker of flies, rodents, and humans generates less robust circadian output signals across normative aging. It is not well understood how changes in light sensitivity might contribute to this phenomenon. In the present study, we summarize results from an extended data series (n = 5681) showing that the locomotor activity rhythm of aged Drosophila can phase-shift normally to intermittently spaced episodes of bright polychromatic light exposure (600 lx) but that deficits emerge in response to 8, 16, and 120-millisecond flashes of narrowband blue (λm, 452 nm) and green (λm, 525 nm) LED light. For blue, phase-resetting of the activity rhythm of older flies is not as energy efficient as it is in younger flies at the fastest flash-exposures tested (8 milliseconds), suggesting there might be different floors of light duration necessary to incur photohabituation in each age group. For green, the responses of older flies are universally crippled relative to those of younger flies across the slate of protocols we tested. The difference in green flash photosensitivity is one of the most salient age-related phenotypes that has been documented in the circadian phase-shifting literature thus far. These data provide further impetus for investigations on pacemaker aging and how it might relate to changes in the circadian system's responses to particular sequences of light exposure tuned for wavelength, intensity, duration, and tempo.
Collapse
Affiliation(s)
| | | | - Jamie M Zeitzer
- Department of Psychiatry and Behavioral Sciences and Stanford Center for Sleep Sciences and Medicine, Stanford University, Stanford, CA, USA; Mental Illness Research, Education and Clinical Center, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
| | - Fabian-Xosé Fernandez
- Department of Psychology, University of Arizona, Tucson, AZ, USA; Department of Neurology, University of Arizona, Tucson, AZ, USA; BIO5 and McKnight Brain Research Institutes, University of Arizona, Tucson, AZ, USA.
| |
Collapse
|
15
|
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.
Collapse
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
| |
Collapse
|
16
|
St. Hilaire MA. Modeling (circadian). PROGRESS IN BRAIN RESEARCH 2022; 273:181-198. [DOI: 10.1016/bs.pbr.2022.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
17
|
OUP accepted manuscript. Brain 2022; 145:3225-3235. [DOI: 10.1093/brain/awac147] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/23/2022] [Accepted: 04/07/2022] [Indexed: 11/14/2022] Open
|
18
|
Beyond irradiance: Visual signals influencing mammalian circadian function. PROGRESS IN BRAIN RESEARCH 2022; 273:145-169. [DOI: 10.1016/bs.pbr.2022.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
19
|
Spectral sensitivity of circadian phase resetting, melatonin suppression and acute alerting effects of intermittent light exposure. Biochem Pharmacol 2021; 191:114504. [DOI: 10.1016/j.bcp.2021.114504] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 12/19/2022]
|
20
|
Exposure to Short Wavelength-Enriched White Light and Exercise Improves Alertness and Performance in Operational NASA Flight Controllers Working Overnight Shifts. J Occup Environ Med 2021; 63:111-118. [PMID: 33065729 DOI: 10.1097/jom.0000000000002054] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE We evaluated the efficacy of a combined short-wavelength-enriched white light and exercise fatigue countermeasure during breaks for flight controllers working overnight shifts. METHODS Twenty NASA flight controllers were studied for two blocks of nightshifts in ISS mission control, randomized to either the control or countermeasure condition. The countermeasure constituted passive exposure to blue-enriched polychromatic lighting for three 20-minute intervals, which included 10 minutes of exercise and occurred before and twice during their shifts. Alertness, performance, and mood were evaluated. RESULTS Flight controllers reported being significantly more alert (P < 0.0001) and happy (P = 0.003) and had faster reaction times (10% slowest responses; P < 0.05) during the countermeasure condition compared to control. CONCLUSIONS The combined light and exercise countermeasure improved alertness, performance, and mood in shift workers overnight. Further research is necessary to determine their relative contribution.
Collapse
|
21
|
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.
Collapse
|
22
|
Prayag AS, Münch M, Aeschbach D, Chellappa SL, Gronfier C. Reply to Bracke et al. Comment on "Prayag et al. Light Modulation of Human Clocks, Wake, and Sleep. Clocks&Sleep 2019, 1, 193-208". Clocks Sleep 2021; 3:398-402. [PMID: 34287255 PMCID: PMC8293177 DOI: 10.3390/clockssleep3030026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 06/07/2021] [Indexed: 02/08/2023] Open
Abstract
We thank Bracke and colleagues [...].
Collapse
Affiliation(s)
- Abhishek S. Prayag
- Lyon Neuroscience Research Center (CRNL), Waking Team, Inserm UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, 69000 Lyon, France;
| | - Mirjam Münch
- Centre for Public Health Research, Massey University, Wellington 6140, New Zealand;
| | - Daniel Aeschbach
- Department of Sleep and Human Factors Research, Institute of Aerospace Medicine, German Aerospace Center (DLR), 51170 Cologne, Germany;
- Faculty of Medicine, University of Bonn, 53127 Bonn, Germany
- Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115, USA;
| | - Sarah L. Chellappa
- Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115, USA;
- Medical Chronobiology Program, Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA 02115, USA
| | - Claude Gronfier
- Lyon Neuroscience Research Center (CRNL), Waking Team, Inserm UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, 69000 Lyon, France;
| |
Collapse
|
23
|
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.
Collapse
|
24
|
Rea MS, Nagare R, Figueiro MG. Modeling Circadian Phototransduction: Quantitative Predictions of Psychophysical Data. Front Neurosci 2021; 15:615322. [PMID: 33613181 PMCID: PMC7893103 DOI: 10.3389/fnins.2021.615322] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 01/08/2021] [Indexed: 01/29/2023] Open
Abstract
A revised computational model of circadian phototransduction is presented. The first step was to characterize the spectral sensitivity of the retinal circuit using suppression of the synthesis of melatonin by the pineal gland at night as the outcome measure. From the spectral sensitivity, circadian light was defined. Circadian light, thereby rectifies any spectral power distribution into a single, instantaneous photometric quantity. The second step was to characterize the circuit’s response characteristic to different amounts of circadian light from threshold to saturation. By doing so a more complete instantaneous photometric quantity representing the circadian stimulus was defined in terms of both the spectral sensitivity and the response magnitude characteristic of the circadian phototransduction circuit. To validate the model of the circadian phototransduction circuit, it was necessary to augment the model to account for different durations of the circadian stimulus and distribution of the circadian stimulus across the retina. Two simple modifications to the model accounted for the duration and distribution of continuous light exposure during the early biological night. A companion paper (https://www.frontiersin.org/articles/10.3389/fnins.2020.615305/full) provides a neurophysiological foundation for the model parameters.
Collapse
Affiliation(s)
- Mark S Rea
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, United States.,Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Rohan Nagare
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, United States.,Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Mariana G Figueiro
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, United States.,Icahn School of Medicine at Mount Sinai, New York, NY, United States
| |
Collapse
|
25
|
Meng Y, Tao Z, Zhou S, Da W, Tao L. Research Hot Spots and Trends on Melatonin From 2000 to 2019. Front Endocrinol (Lausanne) 2021; 12:753923. [PMID: 34917024 PMCID: PMC8669723 DOI: 10.3389/fendo.2021.753923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 11/09/2021] [Indexed: 12/25/2022] Open
Abstract
Research on melatonin remains one of the major hot spots in the field of disease treatment, but relevant data are numerous. The purpose of this study was to quantitatively and qualitatively analyze the progress of melatonin research through the method of bibliometrics and to predict hot spots and trends in melatonin research. This study retrieved all the studies on melatonin from 2000 to 2019 in the Web of Science and PubMed and analysed the publishing trends in the literature on a bibliometric online analysis platform and CiteSpace software. The research results were also visually analysed to summarize melatonin research hot spots through gCLUTO and pubMR. The study retrieved a total of 20,351 publications, of which the number of US publications ranked first, accounting for 21.46%, with the greatest impact (centrality = 0.31). The University of Texas Health Science Center at San Antonio and Harvard University had the highest average number of citations at 43.19 and 33.96, respectively. Journal of Pineal Research had the highest average number of citations in 2,993 journals. Professor Reiter made the largest contribution to this area. We further analysed 100 highly cited articles for clinical applications and ongoing related clinical drug trials based on the first hot spot. We systematically analysed melatonin for nearly 20 years while predicting the main research trends in the future, which may provide new directions and ideas for melatonin research. The structure and normal physiological functions of melatonin have been intensively studied in the past few years. And clinical application research and target of melatonin treatment for different diseases and target-based drug design will certainly become the focus of melatonin research.
Collapse
|
26
|
Optimal adjustment of the human circadian clock in the real world. PLoS Comput Biol 2020; 16:e1008445. [PMID: 33370265 PMCID: PMC7808694 DOI: 10.1371/journal.pcbi.1008445] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 01/14/2021] [Accepted: 10/15/2020] [Indexed: 11/23/2022] Open
Abstract
Which suggestions for behavioral modifications, based on mathematical models, are most likely to be followed in the real world? We address this question in the context of human circadian rhythms. Jet lag is a consequence of the misalignment of the body’s internal circadian (~24-hour) clock during an adjustment to a new schedule. Light is the clock’s primary synchronizer. Previous research has used mathematical models to compute light schedules that shift the circadian clock to a new time zone as quickly as possible. How users adjust their behavior when provided with these optimal schedules remains an open question. Here, we report data collected by wearables from more than 100 travelers as they cross time zones using a smartphone app, Entrain. We find that people rarely follow the optimal schedules generated through mathematical modeling entirely, but travelers who better followed the optimal schedules reported more positive moods after their trips. Using the data collected, we improve the optimal schedule predictions to accommodate real-world constraints. We also develop a scheduling algorithm that allows for the computation of approximately optimal schedules "on-the-fly" in response to disruptions. User burnout may not be critically important as long as the first parts of a schedule are followed. These results represent a crucial improvement in making the theoretical results of past work viable for practical use and show how theoretical predictions based on known human physiology can be efficiently used in real-world settings. Jet lag, a significant problem for travelers and shift workers, occurs when our body’s internal circadian (~24-hour) clock is misaligned with the time of day in the environment. Such circadian misalignment can lead to decreased performance, impaired sleep, and increased risk for severe health conditions, ranging from cancer to cardiovascular disease. Previous work has proposed mathematically optimal schedules, based on mathematical models of the human circadian pacemaker, to overcome jet lag in minimal time. Here, we use data collected from over 100 travelers by a mobile app to track when users followed or deviated from optimal schedules. Better adherence to the schedules yielded better outcomes. We also propose more practical schedules, which can be adjusted to the real-world challenges in overcoming jet lag. Our work sets the stage for changing human behaviors in other domains by computing personalized recommendations from mathematical models.
Collapse
|
27
|
Moreno CRC, Wright K, Skene DJ, Louzada FM. Phenotypic plasticity of circadian entrainment under a range of light conditions. Neurobiol Sleep Circadian Rhythms 2020; 9:100055. [PMID: 32923743 PMCID: PMC7475273 DOI: 10.1016/j.nbscr.2020.100055] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 11/25/2022] Open
Abstract
The response to a zeitgeber, particularly the light/dark cycle, may vary phenotypically. Phenotypic plasticity can be defined as the ability of one genome to express different phenotypes in response to environmental variation. In this opinion paper, we present some evidence that one of the most prominent effects of the introduction of electric light to the everyday life of humans is a significant increase in phenotypic plasticity and differences in interindividual phases of entrainment. We propose that the healthy limits of phenotypic plasticity have been surpassed in contemporary society. Electric light increased phenotypic plasticity in humans and differences in interindividual phases of entrainment. Healthy limits of phenotypic plasticity have been surpassed in contemporary society. The correlation between biological time (DLMO) and behavioral time (MSFsc) is reduced in the population without access to electrical light.
Collapse
Affiliation(s)
- C R C Moreno
- School of Public Health, University of São Paulo, Brazil.,Stress Research Institute, Department of Psychology, Stockholm University, Sweden
| | - K Wright
- Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, USA
| | - D J Skene
- Chronobiology, Faculty of Health & Medical Sciences, University of Surrey, UK
| | - F M Louzada
- Department of Physiology, Federal University of Paraná, Brazil
| |
Collapse
|
28
|
Hannay KM, Moreno JP. Integrating wearable data into circadian models. CURRENT OPINION IN SYSTEMS BIOLOGY 2020; 22:32-38. [PMID: 38125310 PMCID: PMC10732358 DOI: 10.1016/j.coisb.2020.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
The emergence of wearable health sensors in the last decade has the potential to revolutionize the study of sleep and circadian rhythms. In particular, recent progress has been made in the use of mathematical models in the prediction of a patient's internal circadian state using data measured by wearable devices. This is a vital step in our ability to identify optimal circadian timing for health interventions. We review the available data for fitting circadian phase models with a focus on wearable data sets. Finally, we review the current modeling paradigms and explore avenues for developing personalized parameter sets in limit cycle oscillator models in order to further improve prediction accuracy.
Collapse
Affiliation(s)
- Kevin M Hannay
- Department of Mathematics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Jennette P Moreno
- USDA/ARS Childrens Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| |
Collapse
|
29
|
Abstract
The temporal organization of molecular and physiological processes is driven by environmental and behavioral cycles as well as by self-sustained molecular circadian oscillators. Quantification of phase, amplitude, period, and disruption of circadian oscillators is essential for understanding their contribution to sleep-wake disorders, social jet lag, interindividual differences in entrainment, and the development of chrono-therapeutics. Traditionally, assessment of the human circadian system, and the output of the SCN in particular, has required collection of long time series of univariate markers such as melatonin or core body temperature. Data were collected in specialized laboratory protocols designed to control for environmental and behavioral influences on rhythmicity. These protocols are time-consuming, expensive, and not practical for assessing circadian status in patients or in participants in epidemiologic studies. Novel approaches for assessment of circadian parameters of the SCN or peripheral oscillators have been developed. They are based on machine learning or mathematical model-informed analyses of features extracted from 1 or a few samples of high-dimensional data, such as transcriptomes, metabolomes, long-term simultaneous recording of activity, light exposure, skin temperature, and heart rate or in vitro approaches. Here, we review whether these approaches successfully quantify parameters of central and peripheral circadian oscillators as indexed by gold standard markers. Although several approaches perform well under entrained conditions when sleep occurs at night, the methods either perform worse in other conditions such as shift work or they have not been assessed under any conditions other than entrainment and thus we do not yet know how robust they are. Novel approaches for the assessment of circadian parameters hold promise for circadian medicine, chrono-therapeutics, and chrono-epidemiology. There remains a need to validate these approaches against gold standard markers, in individuals of all sexes and ages, in patient populations, and, in particular, under conditions in which behavioral cycles are displaced.
Collapse
Affiliation(s)
- Derk-Jan Dijk
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK.,UK Dementia Research Institute, University of Surrey
| | - Jeanne F Duffy
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| |
Collapse
|
30
|
Foster RG, Hughes S, Peirson SN. Circadian Photoentrainment in Mice and Humans. BIOLOGY 2020; 9:biology9070180. [PMID: 32708259 PMCID: PMC7408241 DOI: 10.3390/biology9070180] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/03/2020] [Accepted: 07/05/2020] [Indexed: 12/26/2022]
Abstract
Light around twilight provides the primary entrainment signal for circadian rhythms. Here we review the mechanisms and responses of the mouse and human circadian systems to light. Both utilize a network of photosensitive retinal ganglion cells (pRGCs) expressing the photopigment melanopsin (OPN4). In both species action spectra and functional expression of OPN4 in vitro show that melanopsin has a λmax close to 480 nm. Anatomical findings demonstrate that there are multiple pRGC sub-types, with some evidence in mice, but little in humans, regarding their roles in regulating physiology and behavior. Studies in mice, non-human primates and humans, show that rods and cones project to and can modulate the light responses of pRGCs. Such an integration of signals enables the rods to detect dim light, the cones to detect higher light intensities and the integration of intermittent light exposure, whilst melanopsin measures bright light over extended periods of time. Although photoreceptor mechanisms are similar, sensitivity thresholds differ markedly between mice and humans. Mice can entrain to light at approximately 1 lux for a few minutes, whilst humans require light at high irradiance (>100’s lux) and of a long duration (>30 min). The basis for this difference remains unclear. As our retinal light exposure is highly dynamic, and because photoreceptor interactions are complex and difficult to model, attempts to develop evidence-based lighting to enhance human circadian entrainment are very challenging. A way forward will be to define human circadian responses to artificial and natural light in the “real world” where light intensity, duration, spectral quality, time of day, light history and age can each be assessed.
Collapse
|
31
|
Lee SI, Kinoshita S, Noguchi A, Eto T, Ohashi M, Nishimura Y, Maeda K, Motomura Y, Awata Y, Higuchi S. Melatonin suppression during a simulated night shift in medium intensity light is increased by 10-minute breaks in dim light and decreased by 10-minute breaks in bright light. Chronobiol Int 2020; 37:897-909. [PMID: 32326827 DOI: 10.1080/07420528.2020.1752704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Exposure to light at night results in disruption of endogenous circadian rhythmicity and/or suppression of pineal melatonin, which can consequently lead to acute or chronic adverse health problems. In the present study, we investigated whether exposure to very dim light or very bright light for a short duration influences melatonin suppression, subjective sleepiness, and performance during exposure to constant moderately bright light. Twenty-four healthy male university students were divided into two experimental groups: Half of them (mean age: 20.0 ± 0.9 years) participated in an experiment for short-duration (10 min) light conditions of medium intensity light (430 lx, medium breaks) vs. very dim light (< 1 lx, dim breaks) and the other half (mean age: 21.3 ± 2.5 years) participated in an experiment for short-duration light conditions of medium intensity light (430 lx, medium breaks) vs. very bright light (4700 lx, bright breaks). Each simulated night shift consisting of 5 sets (each including 50-minute night work and 10-minute break) was performed from 01:00 to 06:00 h. The subjects were exposed to medium intensity light (550 lx) during the night work. Each 10-minute break was conducted every hour from 02:00 to 06:00 h. Salivary melatonin concentrations were measured, subjective sleepiness was assessed, the psychomotor vigilance task was performed at hourly intervals from 21:00 h until the end of the experiment. Compared to melatonin suppression between 04:00 and 06:00 h in the condition of medium breaks, the condition of dim breaks significantly promoted melatonin suppression and the condition of bright breaks significantly diminished melatonin suppression. However, there was no remarkable effect of either dim breaks or bright breaks on subjective sleepiness and performance of the psychomotor vigilance task. Our findings suggest that periodic exposure to light for short durations during exposure to a constant light environment affects the sensitivity of pineal melatonin to constant light depending on the difference between light intensities in the two light conditions (i.e., short light exposure vs. constant light exposure). Also, our findings indicate that exposure to light of various intensities at night could be a factor influencing the light-induced melatonin suppression in real night work settings.
Collapse
Affiliation(s)
- Sang-Il Lee
- Department of Human Science, Faculty of Design, Kyushu University , Fukuoka, Japan.,Division of Human Environmental Systems, Faculty of Engineering, Hokkaido University , Sapporo, Japan
| | - Saki Kinoshita
- Department of Kansei Science, Graduate School of Integrated Frontier Science, Kyushu University , Fukuoka, Japan
| | - Anna Noguchi
- Department of Kansei Science, Graduate School of Integrated Frontier Science, Kyushu University , Fukuoka, Japan
| | - Taisuke Eto
- Department of Kansei Science, Graduate School of Integrated Frontier Science, Kyushu University , Fukuoka, Japan
| | - Michihiro Ohashi
- Department of Kansei Science, Graduate School of Integrated Frontier Science, Kyushu University , Fukuoka, Japan
| | - Yuki Nishimura
- Department of Kansei Science, Graduate School of Integrated Frontier Science, Kyushu University , Fukuoka, Japan.,Occupational Stress and Health Management Research Group, National Institute of Occupational Safety and Health , Kawasaki, Japan
| | - Kaho Maeda
- Ground Facilities Department, Japan Aerospace Exploration Agency , Tsukuba, Japan
| | - Yuki Motomura
- Department of Human Science, Faculty of Design, Kyushu University , Fukuoka, Japan
| | - Yasuhiro Awata
- Ground Facilities Department, Japan Aerospace Exploration Agency , Tsukuba, Japan
| | - Shigekazu Higuchi
- Department of Human Science, Faculty of Design, Kyushu University , Fukuoka, Japan
| |
Collapse
|
32
|
Rahman SA, Wright KP, Lockley SW, Czeisler CA, Gronfier C. Characterizing the temporal Dynamics of Melatonin and Cortisol Changes in Response to Nocturnal Light Exposure. Sci Rep 2019; 9:19720. [PMID: 31873098 PMCID: PMC6928018 DOI: 10.1038/s41598-019-54806-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 11/06/2019] [Indexed: 01/11/2023] Open
Abstract
We studied the dynamics of melatonin suppression and changes in cortisol levels in humans in response to light exposure at night using high-frequency blood sampling. Twenty-one young healthy participants were randomized to receive either intermittent bright (~9,500 lux) light (IBL), continuous bright light (CBL) or continuous dim (~1 lux) light (VDL) for 6.5 h during the biological night (n = 7 per condition). Melatonin suppression occurred rapidly within the first 5 min and continued until the end of each IBL stimuli (t1/2 = ~13 min). Melatonin recovery occurred more slowly between IBL stimuli (half-maximal recovery rate of ~46 min). Mean melatonin suppression (~40%) and recovery (~50%) were similar across IBL stimuli. Suppression dynamics under CBL were also rapid (t1/2 = ~18 min), with no recovery until the light exposure ended. There was a significant linear increase of cortisol levels between the start and end of each IBL stimulus. Under CBL conditions cortisol showed trimodal changes with an initial linear activating phase, followed by an exponential inhibitory phase, and a final exponential recovery phase. These results show that light exposure at night affects circadian driven hormones differently and that outcomes are influenced by the duration and pattern of light exposure.
Collapse
Affiliation(s)
- Shadab A Rahman
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham & Women's Hospital, Boston, MA, USA.
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA.
| | - Kenneth P Wright
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham & Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
- Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Steven W Lockley
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham & Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Charles A Czeisler
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham & Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Claude Gronfier
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham & Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
- Lyon Neuroscience Research Center, Waking team, Inserm UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, F-69000, Lyon, France
| |
Collapse
|
33
|
Abstract
Mathematical models have a long and influential history in the study of human circadian rhythms. Accurate predictive models for the human circadian light response have been used to study the impact of a host of light exposures on the circadian system. However, generally, these models do not account for the physiological basis of these rhythms. We illustrate a new paradigm for deriving models of the human circadian light response. Beginning from a high-dimensional model of the circadian neural network, we systematically derive low-dimensional models using an approach motivated by experimental measurements of circadian neurons. This systematic reduction allows for the variables and parameters of the derived model to be interpreted in a physiological context. We fit and validate the resulting models to a library of experimental measurements. Finally, we compare model predictions for experimental measurements of light levels and discuss the differences between our model’s predictions and previous models. Our modeling paradigm allows for the integration of experimental measurements across the single-cell, tissue, and behavioral scales, thereby enabling the development of accurate low-dimensional models for human circadian rhythms.
Collapse
Affiliation(s)
- Kevin M. Hannay
- Department of Mathematics, Schreiner University, Kerrville, Texas
| | - Victoria Booth
- Department of Mathematics, University of Michigan, Ann Arbor, Michigan
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan
| | - Daniel B. Forger
- Department of Mathematics, University of Michigan, Ann Arbor, Michigan
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan
| |
Collapse
|
34
|
Kronauer RE, Hilaire MA, Rahman SA, Czeisler CA, Klerman EB. An Exploration of the Temporal Dynamics of Circadian Resetting Responses to Short- and Long-Duration Light Exposures: Cross-Species Consistencies and Differences. J Biol Rhythms 2019; 34:497-514. [PMID: 31368391 PMCID: PMC7363039 DOI: 10.1177/0748730419862702] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Light is the most effective environmental stimulus for shifting the mammalian circadian pacemaker. Numerous studies have been conducted across multiple species to delineate wavelength, intensity, duration, and timing contributions to the response of the circadian pacemaker to light. Recent studies have revealed a surprising sensitivity of the human circadian pacemaker to short pulses of light. Such responses have challenged photon counting-based theories of the temporal dynamics of the mammalian circadian system to both short- and long-duration light stimuli. Here, we collate published light exposure data from multiple species, including gerbil, hamster, mouse, and human, to investigate these temporal dynamics and explore how the circadian system integrates light information at both short- and long-duration time scales to produce phase shifts. Based on our investigation of these data sets, we propose 3 new interpretations: (1) intensity and duration are independent factors of total phase shift magnitude, (2) the possibility of a linear/log temporal function of light duration that is universal for all intensities for durations less than approximately 12 min, and (3) a potential universal minimum light duration of ~0.7 sec that describes a "dead zone" of light stimulus. We show that these properties appear to be consistent across mammalian species. These interpretations, if confirmed by further experiments, have important practical implications in terms of understanding the underlying physiology and for the design of lighting regimens to reset the mammalian circadian pacemaker.
Collapse
Affiliation(s)
- Richard E. Kronauer
- School of Engineering and Applied Sciences, Harvard University, Cambridge, MA USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Melissa A. Hilaire
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Shadab A. Rahman
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Charles A. Czeisler
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Elizabeth B. Klerman
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women’s Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
35
|
Abstract
Humans live in a 24-hour environment, in which light and darkness follow a diurnal pattern. Our circadian pacemaker, the suprachiasmatic nuclei (SCN) in the hypothalamus, is entrained to the 24-hour solar day via a pathway from the retina and synchronises our internal biological rhythms. Rhythmic variations in ambient illumination impact behaviours such as rest during sleep and activity during wakefulness as well as their underlying biological processes. Rather recently, the availability of artificial light has substantially changed the light environment, especially during evening and night hours. This may increase the risk of developing circadian rhythm sleep-wake disorders (CRSWD), which are often caused by a misalignment of endogenous circadian rhythms and external light-dark cycles. While the exact relationship between the availability of artificial light and CRSWD remains to be established, nocturnal light has been shown to alter circadian rhythms and sleep in humans. On the other hand, light can also be used as an effective and noninvasive therapeutic option with little to no side effects, to improve sleep,mood and general well-being. This article reviews our current state of knowledge regarding the effects of light on circadian rhythms, sleep, and mood.
Collapse
Affiliation(s)
- Christine Blume
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel (UPK), Basel, Switzerland.,Transfaculty Research Platform Molecular and Cognitive Neurosciences (MCN), University of Basel, Basel, Switzerland.,Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria
| | - Corrado Garbazza
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel (UPK), Basel, Switzerland.,Transfaculty Research Platform Molecular and Cognitive Neurosciences (MCN), University of Basel, Basel, Switzerland
| | - Manuel Spitschan
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel (UPK), Basel, Switzerland.,Transfaculty Research Platform Molecular and Cognitive Neurosciences (MCN), University of Basel, Basel, Switzerland.,Department of Experimental Psychology, University of Oxford, Oxford, UK
| |
Collapse
|
36
|
Spitschan M, Stefani O, Blattner P, Gronfier C, Lockley SW, Lucas RJ. How to Report Light Exposure in Human Chronobiology and Sleep Research Experiments. Clocks Sleep 2019; 1:280-289. [PMID: 31281903 PMCID: PMC6609447 DOI: 10.3390/clockssleep1030024] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 06/13/2019] [Indexed: 02/07/2023] Open
Abstract
Exposure to light has short- and long-term impacts on non-visual responses in humans. While many aspects related to non-visual light sensitivity have been characterised (such as the action spectrum for melatonin suppression), much remains to be elucidated. Here, we provide a set of minimum reporting guidelines for reporting the stimulus conditions involving light as an intervention in chronobiology, sleep research and environmental psychology experiments. Corresponding to the current state-of-the-art knowledge (June 2019), these are (i) measure and report the spectral power distribution of the acute stimulus from the observer's point of view; (ii) measure and report the spectral power distribution of the background light environment from the observer's point of view; (iii), make spectra available in tabulated form, (iv) report α-opic (ir)radiances and illuminance; (v) describe the timing properties of stimulus (duration and pattern); (vi) describe the spatial properties of stimulus (spatial arrangement and extent), and (vii) report measurement conditions and equipment. We supplement the minimum reporting guidelines with optional reporting suggestions and discuss limitations of the reporting scheme.
Collapse
Affiliation(s)
- Manuel Spitschan
- Department of Experimental Psychology, University of Oxford, Oxford OX2 6GG, UK
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel (UPK), 4002 Basel, Switzerland
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, 4055 Basel, Switzerland
| | - Oliver Stefani
- Centre for Chronobiology, Psychiatric Hospital of the University of Basel (UPK), 4002 Basel, Switzerland
- Transfaculty Research Platform Molecular and Cognitive Neurosciences, University of Basel, 4055 Basel, Switzerland
| | - Peter Blattner
- Federal Institute of Metrology METAS, 3003 Bern-Wabern, Switzerland
| | - Claude Gronfier
- Lyon Neuroscience Research Center, Waking team, INSERM UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, F-69000 Lyon, France
| | - Steven W. Lockley
- Division of Sleep and Circadian Disorders, Brigham and Women’s Hospital, Boston, MA 02115, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115, USA
- Monash Institute of Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, 18 Innovation Walk, Clayton, VIC 3800, Australia
| | - Robert J. Lucas
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| |
Collapse
|
37
|
Fernandez F. Circadian Responses to Fragmented Light: Research Synopsis in Humans. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2019; 92:337-348. [PMID: 31249494 PMCID: PMC6585514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Light is the chief signal used by the human circadian pacemaker to maintain precise biological timekeeping. Though it has been historically assumed that light resets the pacemaker's rhythm in a dose-dependent fashion, a number of studies report enhanced circadian photosensitivity to the initial moments of light exposure, such that there are quickly diminishing returns on phase-shifting the longer the light is shown. In the current review, we summarize findings from a family of experiments conducted over two decades in the research wing of the Brigham and Women's Hospital that examined the human pacemaker's responses to standardized changes in light patterns generated from an overhead fluorescent ballast. Across several hundred days of laboratory recording, the research group observed phase-shifts in the body temperature and melatonin rhythms that scaled with illuminance. However, as suspected, phase resetting was optimized when exposure occurred as a series of minute-long episodes separated by periods of intervening darkness. These observations set the stage for a more recent program of study at Stanford University that evaluated whether the human pacemaker was capable of integrating fragmented bursts of light in much the same way it perceived steady luminance. The results here suggest that ultra-short durations of light-lasting just 1-2 seconds in total-can elicit pacemaker responses rivaling those created by continuous hour-long stimulation if those few seconds of light are evenly distributed across the hour as discreet 2-millisecond pulses. We conclude our review with a brief discussion of these findings and their potential application in future phototherapy techniques.
Collapse
Affiliation(s)
- Fabian Fernandez
- To whom all correspondence should be addressed: Fabian Fernandez, PhD, Department of Psychology, 1501 N. Campbell Avenue Life Sciences North, Room 349, Tucson, Arizona, 85724;
| |
Collapse
|
38
|
Wong LR, Flynn-Evans E, Ruskin KJ. Fatigue Risk Management: The Impact of Anesthesiology Residents' Work Schedules on Job Performance and a Review of Potential Countermeasures. Anesth Analg 2019; 126:1340-1348. [PMID: 29049076 DOI: 10.1213/ane.0000000000002548] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Long duty periods and overnight call shifts impair physicians' performance on measures of vigilance, psychomotor functioning, alertness, and mood. Anesthesiology residents typically work between 64 and 70 hours per week and are often required to work 24 hours or overnight shifts, sometimes taking call every third night. Mitigating the effects of sleep loss, circadian misalignment, and sleep inertia requires an understanding of the relationship among work schedules, fatigue, and job performance. This article reviews the current Accreditation Council for Graduate Medical Education guidelines for resident duty hours, examines how anesthesiologists' work schedules can affect job performance, and discusses the ramifications of overnight and prolonged duty hours on patient safety and resident well-being. We then propose countermeasures that have been implemented to mitigate the effects of fatigue and describe how training programs or practice groups who must work overnight can adapt these strategies for use in a hospital setting. Countermeasures include the use of scheduling interventions, strategic naps, microbreaks, caffeine use during overnight and extended shifts, and the use of bright lights in the clinical setting when possible or personal blue light devices when the room lights must be turned off. Although this review focuses primarily on anesthesiology residents in training, many of the mitigation strategies described here can be used effectively by physicians in practice.
Collapse
Affiliation(s)
- Lily R Wong
- From the San Jose State University Research Foundation, San Jose, California.,Human Factors Research Division, NASA Ames Research Center, Moffett Field, California
| | - Erin Flynn-Evans
- Human Factors Research Division, NASA Ames Research Center, Moffett Field, California
| | - Keith J Ruskin
- Department of Anesthesia and Critical Care, University of Chicago School of Medicine, Chicago, Illinois
| |
Collapse
|
39
|
Prayag AS, Najjar RP, Gronfier C. Melatonin suppression is exquisitely sensitive to light and primarily driven by melanopsin in humans. J Pineal Res 2019; 66:e12562. [PMID: 30697806 DOI: 10.1111/jpi.12562] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 01/01/2019] [Accepted: 01/19/2019] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Light elicits a range of non-visual responses in humans. Driven predominantly by intrinsically photosensitive retinal ganglion cells (ipRGCs), but also by rods and/or cones, these responses include melatonin suppression. A sigmoidal relationship has been established between melatonin suppression and light intensity; however, photoreceptoral involvement remains unclear. METHODS AND RESULTS In this study, we first modelled the relationships between alpha-opic illuminances and melatonin suppression using an extensive dataset by Brainard and colleagues. Our results show that (a) melatonin suppression is better predicted by melanopic illuminance compared to other alpha-opic illuminances, (b) melatonin suppression is predicted to occur at levels as low as ~1.5 melanopic lux (melanopsin-weighted irradiance 0.2 µW/cm2 ), (c) saturation occurs at 305 melanopic lux (melanopsin-weighted irradiance 36.6 µW/cm2 ). We then tested this melanopsin-weighted illuminance-response model derived from Brainard and colleagues' data and show that it predicts equally well melatonin suppression data from our laboratory, although obtained using different intensities and exposure duration. DISCUSSION Together, our findings suggest that melatonin suppression by monochromatic lights is predominantly driven by melanopsin and that it can be initiated at extremely low melanopic lux levels in experimental conditions. This emphasizes the concern of the non-visual impacts of low light intensities in lighting design and light-emitting devices.
Collapse
Affiliation(s)
- Abhishek S Prayag
- Lyon Neuroscience Research Center, Integrative Physiology of the Brain Arousal Systems, Waking team, Inserm UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, F-69000, Lyon, France
| | - Raymond P Najjar
- Department of Visual Neuroscience, Singapore Eye Research Institute, Singapore
- The Ophthalmology & Visual Sciences ACP, Duke-NUS Medical School, Singapore
| | - Claude Gronfier
- Lyon Neuroscience Research Center, Integrative Physiology of the Brain Arousal Systems, Waking team, Inserm UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, F-69000, Lyon, France
| |
Collapse
|
40
|
Abstract
Light, through its non-imaging forming effects, plays a dominant role on a myriad of physiological functions, including the human sleep–wake cycle. The non-image forming effects of light heavily rely on specific properties such as intensity, duration, timing, pattern, and wavelengths. Here, we address how specific properties of light influence sleep and wakefulness in humans through acute effects, e.g., on alertness, and/or effects on the circadian timing system. Of critical relevance, we discuss how different characteristics of light exposure across the 24-h day can lead to changes in sleep–wake timing, sleep propensity, sleep architecture, and sleep and wake electroencephalogram (EEG) power spectra. Ultimately, knowledge on how light affects sleep and wakefulness can improve light settings at home and at the workplace to improve health and well-being and optimize treatments of chronobiological disorders.
Collapse
|
41
|
Prayag AS, Jost S, Avouac P, Dumortier D, Gronfier C. Dynamics of Non-visual Responses in Humans: As Fast as Lightning? Front Neurosci 2019; 13:126. [PMID: 30890907 PMCID: PMC6411922 DOI: 10.3389/fnins.2019.00126] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 02/04/2019] [Indexed: 12/22/2022] Open
Abstract
The eye drives non-visual (NV) responses to light, including circadian resetting, pupillary reflex and alerting effects. Initially thought to depend on melanopsin-expressing retinal ganglion cells (ipRGCs), classical photopigments play a modulatory role in some of these responses. As most studies have investigated only a limited number of NV functions, generally under conditions of relatively high light levels and long duration of exposure, whether NV functions share similar irradiance sensitivities and response dynamics during light exposure is unknown. We addressed this issue using light exposure paradigms spectrally and spatially tuned to target mainly cones or ipRGCs, and by measuring longitudinally (50 min) several NV responses in 28 men. We demonstrate that the response dynamics of NV functions are faster than previously thought. We find that the brain, the heart, and thermoregulation are activated within 1 to 5 min of light exposure. Further, we show that NV functions do not share the same response sensitivities. While the half-maximum response is only ∼48 s for the tonic pupil diameter, it is ∼12 min for EEG gamma activity. Most NV responses seem to be saturated by low light levels, as low as 90 melanopic lux. Our results also reveal that it is possible to maintain optimal visual performance while modulating NV responses. Our findings have real-life implications. On one hand, light therapy paradigms should be re-evaluated with lower intensities and shorter durations, with the potential of improving patients' compliance. On the other hand, the significant impact of low intensity and short duration light exposures on NV physiology should make us reconsider the potential health consequences of light exposure before bedtime, in particular on sleep and circadian physiology.
Collapse
Affiliation(s)
- Abhishek S Prayag
- Lyon Neuroscience Research Center, Integrative Physiology of the Brain Arousal Systems, Waking Team, Inserm UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Sophie Jost
- ENTPE, LGCB, Université de Lyon, Lyon, France
| | | | | | - Claude Gronfier
- Lyon Neuroscience Research Center, Integrative Physiology of the Brain Arousal Systems, Waking Team, Inserm UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| |
Collapse
|
42
|
Occupational Health and Sleep Issues in Underserved Populations. PHYSICIAN ASSISTANT CLINICS 2019. [DOI: 10.1016/j.cpha.2018.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
43
|
Leger D, Duforez F, Gronfier C. [Treating circadian sleep-wake disorders by light]. Presse Med 2018; 47:1003-1009. [PMID: 30413331 DOI: 10.1016/j.lpm.2018.10.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 10/08/2018] [Indexed: 11/16/2022] Open
Abstract
Phototherapy is one treatment of circadian sleep-wake disorders, which is based on consensual and numerous scientific and clinical evidences. Phototherapy efficiency depends on several light characteristics based on intensity, length of exposure, time of exposure and wavelength. Phototherapy is potentially indicated in the following circadian disorders: advanced sleep-wake phase disorder (ASWPD), delayed sleep-wake phase disorder (DSWPD), non-24-hour sleep-wake rhythm disorder (N24SWD), jet-lag and night-shift work sleep-wake disorders (NSSWD). Phototherapy, acting via the retina, may be avoided in patients with retina disorders, an ophthalmologist should be consulted.
Collapse
Affiliation(s)
- Damien Leger
- AP-HP, HUPC, Hôtel-Dieu de Paris, université Paris Descartes, Centre du Sommeil et de la Vigilance, EA 7330 VIFASOM, 1, place du Parvis Jean-Paul-II, 75004 Paris, France.
| | - François Duforez
- AP-HP, HUPC, Hôtel-Dieu de Paris, université Paris Descartes, Centre du Sommeil et de la Vigilance, EA 7330 VIFASOM, 1, place du Parvis Jean-Paul-II, 75004 Paris, France; European Sleep Center, 9, avenue d'Eylau, 75116 Paris, France
| | - Claude Gronfier
- Université Claude-Bernard Lyon 1, université de Lyon, centre de recherche en neurosciences de Lyon (CRNL), équipe Waking, Inserm UMRS 1028, CNRS UMR 5292, 69000 Lyon, France
| | | |
Collapse
|
44
|
Abstract
Time of day is a critical factor for most biological functions, but concepts from the field of chronobiology have yet to be fully translated to clinical practice. Circadian rhythms, generated internally and synchronised to the external environment, promote function and support survival in almost every living species. Fetal circadian rhythms can be observed in utero from 30weeks gestation, coupled to the maternal rhythm, but synchronise to the external environment only after birth. Important cues for synchronisation include the light/dark cycle, the timing of feeding, and exposure to melatonin in breast milk. Disruption to these cues may occur during admission to the neonatal intensive care unit. This can impair the development of circadian rhythms, and influence survival and function in the neonatal period, with a potential to impact health and well-being throughout adult life. Here we outline the rationale and evidence to support a chronobiological approach to neonatal care.
Collapse
Affiliation(s)
- Helen McKenna
- Critical Care Unit, Royal Free Hospital, Pond Street, London NW3 2QG, UK; Division of Surgery and Interventional Science, University College London, UK.
| | - Irwin Karl Marcel Reiss
- Division of Neonatology, Department of Paediatrics, Erasmus Medical Center, Rotterdam, Netherlands.
| |
Collapse
|
45
|
Responses to Intermittent Light Stimulation Late in the Night Phase Before Dawn. Clocks Sleep 2018; 1:26-41. [PMID: 33089153 PMCID: PMC7509681 DOI: 10.3390/clockssleep1010004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 09/26/2018] [Indexed: 12/04/2022] Open
Abstract
The circadian clock is comprised of two oscillators that independently track sunset (evening) and sunrise (morning), though little is known about how light responses differ in each. Here, we quantified the morning oscillator’s responses to 19 separate pulse trains, collecting observations from over 1300 Drosophila at ZT23. Our results show that the advances in activity onset produced by these protocols depended on the tempo of light administration even when total exposure was conserved across a 15-min window. Moreover, patterns of stimulation previously shown to optimize the evening oscillator’s delay resetting at ZT13 (an hour after dusk) were equally effective for the M oscillator at ZT23 (an hour before dawn), though the morning oscillator was by comparison more photosensitive and could benefit from a greater number of fractionation strategies that better converted light into phase-shifting drive. These data continue to build the case that the reading frames for the pacemaker’s time-of-day estimates at dusk and dawn are not uniform and suggest that the “photologic” for the evening versus morning oscillator’s resetting might be dissociable.
Collapse
|
46
|
Ovid D, Hayes TB, Bentley GE. Melatonin Administration Methods for Research in Mammals and Birds. J Biol Rhythms 2018; 33:567-588. [PMID: 30246597 DOI: 10.1177/0748730418795802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Endocrine research in animals often entails exogenous hormone administration. Special issues arise when developing administration protocols for hormones with circadian and seasonal periodicity. This article reviews various methods for the exogenous administration of hormones with such periodicities by focusing on melatonin. We discuss that methodological variations across studies can affect experimental results. Melatonin administration techniques used in vertebrates includes infusion pumps, beeswax pellets, oral administration, injections, SILASTIC capsules, osmotic pumps, transdermal delivery, beads, and sponges.
Collapse
Affiliation(s)
- Dax Ovid
- University of California, Berkeley, CA, USA
| | | | | |
Collapse
|
47
|
Rahman SA, St Hilaire MA, Gronfier C, Chang AM, Santhi N, Czeisler CA, Klerman EB, Lockley SW. Functional decoupling of melatonin suppression and circadian phase resetting in humans. J Physiol 2018; 596:2147-2157. [PMID: 29707782 DOI: 10.1113/jp275501] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 02/02/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS There is assumed to be a monotonic association between melatonin suppression and circadian phase resetting induced by light exposure. We tested the association between melatonin suppression and phase resetting in humans. Sixteen young healthy participants received nocturnal bright light (∼9500 lux) exposure of continuous or intermittent patterns, and different durations ranging from 12 min to 6.5 h. Intermittent exposure patterns showed significant phase shifts with disproportionately less melatonin suppression. Each and every bright light stimulus in an intermittent exposure pattern induced a similar degree of melatonin suppression, but did not appear to cause an equal magnitude of phase shift. These results suggest that phase shifts and melatonin suppression are functionally independent such that one cannot be used as a proxy measure of the other. ABSTRACT Continuous experimental light exposures show that, in general, the conditions that produce greater melatonin suppression also produce greater phase shift, leading to the assumption that one can be used as a proxy for the other. We tested this association in 16 healthy individuals who participated in a 9-day inpatient protocol by assessing melatonin suppression and phase resetting in response to a nocturnal light exposure (LE) of different patterns: (i) dim-light control (<3 lux; n = 6) or (ii) two 12-min intermittent bright light pulses (IBL) separated by 36 min of darkness (∼9500 lux; n = 10). We compared these results with historical data from additional LE patterns: (i) dim-light control (<3 lux; n = 11); (ii) single continuous bright light exposure of 12 min (n = 9), 1.0 h (n = 10) or 6.5 h (n = 6); or (iii) an IBL light pattern consisting of six 15-min pulses with 1.0 h dim-light recovery intervals between them during a total of 6.5 h (n = 7). All light exposure groups had significantly greater phase-delay shifts than the dim-light control condition (P < 0.0001). While a monotonic association between melatonin suppression and circadian phase shift was observed, intermittent exposure patterns showed significant phase shifts with disproportionately less melatonin suppression. Each and every IBL stimulus induced a similar degree of melatonin suppression, but did not appear to cause an equal magnitude of phase shift. These results suggest unique specificities in how light-induced phase shifts and melatonin suppression are mediated such that one cannot be used as a proxy measure of the other.
Collapse
Affiliation(s)
- Shadab A Rahman
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham & Women's Hospital, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Melissa A St Hilaire
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham & Women's Hospital, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Claude Gronfier
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham & Women's Hospital, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA.,Lyon Neuroscience Research Center, Integrative Physiology of the Brain Arousal Systems (WAKING) team, INSERM UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Université de Lyon, F-69000, Lyon, France
| | - Anne-Marie Chang
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham & Women's Hospital, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Nayantara Santhi
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham & Women's Hospital, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA.,Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, UK
| | - Charles A Czeisler
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham & Women's Hospital, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Elizabeth B Klerman
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham & Women's Hospital, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Steven W Lockley
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham & Women's Hospital, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
48
|
Gaston KJ, Holt LA. Nature, extent and ecological implications of night-time light from road vehicles. J Appl Ecol 2018; 55:2296-2307. [PMID: 30147142 PMCID: PMC6099288 DOI: 10.1111/1365-2664.13157] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 02/09/2018] [Indexed: 11/28/2022]
Abstract
The erosion of night‐time by the introduction of artificial lighting constitutes a profound pressure on the natural environment. It has altered what had for millennia been reliable signals from natural light cycles used for regulating a host of biological processes, with impacts ranging from changes in gene expression to ecosystem processes. Studies of these impacts have focused almost exclusively on those resulting from stationary sources of light emissions, and particularly streetlights. However, mobile sources, especially road vehicle headlights, contribute substantial additional emissions. The ecological impacts of light emissions from vehicle headlights are likely to be especially high because these are (1) focused so as to light roadsides at higher intensities than commonly experienced from other sources, and well above activation thresholds for many biological processes; (2) projected largely in a horizontal plane and thus can carry over long distances; (3) introduced into much larger areas of the landscape than experience street lighting; (4) typically broad “white” spectrum, which substantially overlaps the action spectra of many biological processes and (5) often experienced at roadsides as series of pulses of light (produced by passage of vehicles), a dynamic known to have major biological impacts. The ecological impacts of road vehicle headlights will markedly increase with projected global growth in numbers of vehicles and the road network, increasing the local severity of emissions (because vehicle numbers are increasing faster than growth in the road network) and introducing emissions into areas from which they were previously absent. The effects will be further exacerbated by technological developments that are increasing the intensity of headlight emissions and the amounts of blue light in emission spectra. Synthesis and applications. Emissions from vehicle headlights need to be considered as a major, and growing, source of ecological impacts of artificial night‐time lighting. It will be a significant challenge to minimise these impacts whilst balancing drivers' needs at night and avoiding risk and discomfort for other road users. Nonetheless, there is potential to identify solutions to these conflicts, both through the design of headlights and that of roads.
Emissions from vehicle headlights need to be considered as a major, and growing, source of ecological impacts of artificial night‐time lighting. It will be a significant challenge to minimise these impacts whilst balancing drivers' needs at night and avoiding risk and discomfort for other road users. Nonetheless, there is potential to identify solutions to these conflicts, both through the design of headlights and that of roads.
Collapse
Affiliation(s)
- Kevin J. Gaston
- Environment & Sustainability Institute; University of Exeter; Cornwall UK
- Wissenschaftskolleg zu Berlin, Institute for Advanced Study; Berlin Germany
| | - Lauren A. Holt
- Environment & Sustainability Institute; University of Exeter; Cornwall UK
| |
Collapse
|
49
|
Circadian phase-shifting by light: Beyond photons. Neurobiol Sleep Circadian Rhythms 2018; 5:8-14. [PMID: 31236508 PMCID: PMC6584680 DOI: 10.1016/j.nbscr.2018.03.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 03/23/2018] [Accepted: 03/26/2018] [Indexed: 11/19/2022] Open
Abstract
Circadian entrainment to the solar light:dark schedule is thought to be maintained by a simple photon counting method. According to this hypothesis, the pacemaker adjusts the phase of the body's endogenous rhythms in accordance to the intensity and duration with which it encounters a perceived twilight signal. While previous data have generally supported the hypothesis, more recent analysis has codified other factors besides irradiance that influence the magnitude of resetting responses to light delivered within the same phase of the circadian cycle. In particular, the frequency with which light is alternated with darkness, or whether it's packaged in millisecond flashes versus continuous blocks, can significantly alter the dose-response relationship. Here, we used a drosophilid model to test whether circadian photon-counting trends can be broken with light administration protocols spanning just 15 minutes. In the early part of the delay zone, a 15-min continuous light pulse was fragmented until it could no longer produce a full-magnitude shift of the flies' locomotor activity rhythms. The remaining exposure was then reorganized along various fractionation schemes that employed pulses with different widths and interstimulus intervals. Our results suggest that the pacemaker integrates the phase-shifting effects of equiluminous light differently depending on the stimulus pattern with which light is made available. For example, despite having fewer photons, certain ratios of light and darkness could be optimized on a timescale of seconds and minutes so as to achieve pacemaker resetting close to par with steady luminance. These data provide further evidence that the circadian pacemaker's responses to light entail more than photon counting and motivate continued discussion on how phototherapy can be best optimized in clinical practice to improve conditions linked to circadian impairment.
Collapse
|
50
|
The Acute Effects of Intermittent Light Exposure in the Evening on Alertness and Subsequent Sleep Architecture. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15030524. [PMID: 29543731 PMCID: PMC5877069 DOI: 10.3390/ijerph15030524] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 02/28/2018] [Accepted: 03/13/2018] [Indexed: 01/12/2023]
Abstract
Exposure to bright light is typically intermittent in our daily life. However, the acute effects of intermittent light on alertness and sleep have seldom been explored. To investigate this issue, we employed within-subject design and compared the effects of three light conditions: intermittent bright light (30-min pulse of blue-enriched bright light (~1000 lux, ~6000 K) alternating with 30-min dim normal light (~5 lux, ~3600 K) three times); continuous bright light; and continuous dim light on subjective and objective alertness and subsequent sleep structure. Each light exposure was conducted during the three hours before bedtime. Fifteen healthy volunteers (20 ± 3.4 years; seven males) were scheduled to stay in the sleep laboratory for four separated nights (one for adaptation and the others for the light exposures) with a period of at least one week between nights. The results showed that when compared with dim light, both intermittent light and continuous bright light significantly increased subjective alertness and decreased sleep efficiency (SE) and total sleep time (TST). Intermittent light significantly increased objective alertness than dim light did during the second half of the light-exposure period. Our results suggested that intermittent light was as effective as continuous bright light in their acute effects in enhancing subjective and objective alertness and in negatively impacting subsequent sleep.
Collapse
|