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Chabal SA, Markwald RR, Chinoy ED. Life onboard a submarine: Sleep, fatigue, and lifestyle behaviors of sailors on a circadian-aligned watchstanding schedule. APPLIED ERGONOMICS 2024; 119:104321. [PMID: 38820921 DOI: 10.1016/j.apergo.2024.104321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 03/11/2024] [Accepted: 05/22/2024] [Indexed: 06/02/2024]
Abstract
This study characterizes, for the first time, the lives of U.S. Navy submariners engaged in normal, sea-based operations while following a circadian-aligned 24-h watchstanding schedule. Fifty-eight submarine crewmembers provided objective (actigraphy) and subjective (questionnaires) sleep data, and information about mood and lifestyle behaviors during 30 days underway. Projected performance scores and estimated circadian phase times were also calculated from actigraphy-based sleep/wake data. Submariners' objective (6.62 ± 0.94 h; mean ± SD) and subjective (5.90 ± 1.38 h) daily sleep quantities while underway were largely comparable to the sleep reportedly received by Sailors across other Navy platforms and watchstanding schedules. Additionally, submariners' actigraphy-predicted circadian phases shifted progressively toward better alignment with watchstanding schedules across time. Nevertheless, subjective sleep quality was low, submariners engaged in unfavorable lifestyle behaviors (lack of regular meals and exercise), and participants reported decreased mood at the completion of their underway time. Recommendations for countermeasure development are provided.
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Affiliation(s)
- Sarah A Chabal
- Naval Submarine Medical Research Laboratory, Groton, CT, USA; Sleep, Tactical Efficiency, and Endurance Laboratory, Warfighter Performance Department, Naval Health Research Center, San Diego, CA, USA; Leidos, Inc., Reston, VA, USA.
| | - Rachel R Markwald
- Sleep, Tactical Efficiency, and Endurance Laboratory, Warfighter Performance Department, Naval Health Research Center, San Diego, CA, USA
| | - Evan D Chinoy
- Sleep, Tactical Efficiency, and Endurance Laboratory, Warfighter Performance Department, Naval Health Research Center, San Diego, CA, USA
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Baek D, Baek J, Noh J, Oh Y, Lim L. Toward Healthy Underground Spaces: A Review of Underground Environmental Design Factors and Their Impacts on Users' Physiological and Psychological Health. HERD-HEALTH ENVIRONMENTS RESEARCH & DESIGN JOURNAL 2024:19375867241238470. [PMID: 38606760 DOI: 10.1177/19375867241238470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
OBJECTIVE This study aims to review and synthesize what design factors are associated with the physiological and psychological health of occupants in underground spaces. BACKGROUND The development of underground spaces offers options to global challenges, such as traffic congestion, urban overcrowding, the revitalization of dormant underground areas, disaster mitigation, and adaptation to extreme environments. Despite these advantages, concerns persist about potential adverse effects on human health in these environments. This situation underlines the necessity of systematically identifying concerns and perceptions related to health in underground spaces. METHODS A narrative literature review was conducted to examine the relationship between design factors and health factors across 21 empirical studies. Based on the review of the identified literature, a relationship diagram was developed to depict the interconnections between the identified design and health factors. RESULTS The analysis identified design factors related to the air, sound, light, nature, transport, and spatial context of underground spaces, each of which exerted relationships with occupants' physiological and psychological health factors. The relationship diagram indicated that the psychological factor "feeling of confinement" was mentioned most frequently, suggesting that it is one of the most extensively researched factors in this context. CONCLUSIONS The relationship diagram aims to bridge the existing knowledge gap and set the stage for future research endeavors. The ultimate goal is to refine urban living standards by leveraging the potential of underground spaces while ensuring health and well-being.
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Affiliation(s)
- Daehwa Baek
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Jeongyeop Baek
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Jaechang Noh
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
| | - Yeinn Oh
- College of Design, Georgia Institute of Technology, Atlanta, GA, USA
| | - Lisa Lim
- Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
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Figueiro MG, Pedler D, Plitnick B, Zecena E, Leahy S. Tailored lighting intervention (TLI) for improving sleep-wake cycles in older adults living with dementia. Front Physiol 2023; 14:1290678. [PMID: 38169838 PMCID: PMC10759231 DOI: 10.3389/fphys.2023.1290678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024] Open
Abstract
Introduction: Sleep disturbance is a hallmark of Alzheimer's disease and related dementias, and caregiver stress caused by patients' nighttime wandering, injuries, and agitation are frequently at the root of decisions to move them to assisted living facilities, where typically dim institutional lighting can further exacerbate their sleep problems. This study explored the effects of a circadian-effective lighting intervention on actigraphic sleep measures and subjective assessments of sleep disturbance, depression, and sleep-disturbed behaviors. Methods: Fourteen older adult (≥60 years) participants (11 females, mean age = 84.1 [SD 8.9]), all diagnosed with moderate to severe dementia and sleep disturbance, were recruited from 3 assisted living and memory care facilities. Following a crossover, placebo-controlled design, 3 different lighting modes were used to deliver high levels of circadian stimulus to the participants' eyes for two 8-week intervention periods in a counter balanced order with a 4-week washout between the study's 2 conditions (dim light control vs. active intervention). Actigraphy and questionnaire data were collected over 7-day assessment periods that preceded (baseline weeks 1 and 9) and concluded (post-intervention week 9 and 22) the intervention periods. Actigraphic outcomes included sleep duration, sleep time, sleep efficiency, sleep start time, and sleep end time. Subjective assessments included the Cornell Scale for Depression in Dementia (CSDD), Pittsburgh Sleep Quality Index (PSQI), and Sleep Disorders Inventory (SDI) instruments. Results: Under the active condition, sleep duration significantly (p = 0.018) increased and sleep start time significantly (p = 0.012) advanced after the intervention compared to baseline. Also under the active condition, PSQI (p = 0.012), CSDD (p = 0.007), Sleep Disorders Inventory frequency (p = 0.015), and SDI severity (p = 0.015) scores were significantly lower after the intervention compared to baseline. Discussion: This study demonstrates that a circadian-effective lighting intervention delivering bright days and dark nights improves measures of sleep and mood in dementia patients living in controlled environments.
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Affiliation(s)
- Mariana G. Figueiro
- Department of Population Health Science and Policy, Light and Health Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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Tu Z, Tian F, He J, Wang C, Tian J, Shen X. Independent and joint trajectories of depression and anxiety symptoms among Chinese male sailors throughout a prolonged non-24-h rotating shift schedule at sea: a parallel-process growth mixture modeling approach. BMC Psychiatry 2023; 23:934. [PMID: 38082416 PMCID: PMC10714557 DOI: 10.1186/s12888-023-05389-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 11/21/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND The predictive and protective effect of hardiness on mental health remains unclear among shift workers on non-24-h working schedules. The present study aimed to investigate the independent and joint trajectories of depression and anxiety symptoms and the role of hardiness during a prolonged period of non-24-h shift working schedule. METHODS Four hundred nine Chinese male sailors (working on 18-h watchstanding schedule) were recruited and completed all 5-wave tests through online questionnaires (at Day 1, 14, 28, 42, 55, respectively) during a 55-day sailing. The questionnaires included sociodemographic variables, hardiness, depression and anxiety symptoms. Independent and joint trajectories of depression and anxiety symptoms were estimated by latent growth mixture models. The effect of hardiness on trajectories was examined by logistic regression models. RESULTS 2 and 3 latent trajectories were identified for depression and anxiety symptoms, respectively. Based on initial levels and development trends, 3 distinct joint trajectories of depression and anxiety were identifed and named as: "Low-Inverted U" group (73.6%), "Moderate-Deterioration" group (6.9%), and "High-Stable" group (9.5%). Sailors with higher levels of hardiness were more likely to follow the "Low-Inverted U" trajectory of depression and anxiety symptoms (all p < 0.001). CONCLUSIONS There existed individual differences in the trajectories of depression and anxiety. Hardiness may have a protective effect that can prevent and alleviate depression and anxiety symptoms. Therefore, hardiness-based intervention programs are encouraged among the shift workers on non-24-h working and rest schedules.
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Affiliation(s)
- Zhihao Tu
- Navy Medical Center, Naval Medical University, Shanghai, China
- Qingdao Special Servicemen Recuperation Center of PLA Navy, Qingdao, China
- Department of General Practice, The First Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Fei Tian
- Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jingwen He
- Department of Psychology, Naval Medical University, Shanghai, China
| | - Chuan Wang
- Navy Medical Center, Naval Medical University, Shanghai, China
- Key Laboratory of Molecular Neurobiology of Ministry of Education, Shanghai, China
| | - Jianquan Tian
- Navy Medical Center, Naval Medical University, Shanghai, China.
| | - Xinghua Shen
- Navy Medical Center, Naval Medical University, Shanghai, China.
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Chabal S, Folstein JR, Chinoy ED, Markwald RR, Lieberman HR. Caffeine consumption and sleep in a submarine environment: An observational study. J Sleep Res 2023; 32:e13901. [PMID: 37020175 DOI: 10.1111/jsr.13901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 04/07/2023]
Abstract
Submariners face many environmental and operational challenges to maintaining good sleep, including suboptimal lighting, shift work, and frequent interruptions. Anecdotally, many Sailors consume caffeine to alleviate the effects of poor sleep on alertness, mood, and performance; however, caffeine itself may also degrade sleep quantity and/or quality. This study provides the first exploration of the potential relationship between caffeine use and sleep onboard submarines. Objective measures (wrist actigraphy, available from 45 participants), self-report sleep metrics, and self-reported caffeine consumption were collected from 58 US Navy Sailors before and during a routine submarine underway at sea lasting 30 days. Contrary to expectations, less caffeine was reportedly consumed at sea (232.8 ± 241.1 mg) than on land prior to the underway (M = 284.4 ± 251.7 mg; X2 (1) = 7.43, p = 0.006), positive rather than negative relationships were observed between caffeine consumption and sleep efficiency (F = 6.11, p = 0.02), and negative relationships were observed between caffeine consumption and wake after sleep onset (F = 9.36, p = 0.004) and sleep fragmentation (F = 24.73, p < 0.0001). However, in contrast, higher caffeine consumption was also negatively related to self-reported sleep duration while at sea (F = 4.73, p = 0.03). This observational study is the first to measure relationships between caffeine consumption and sleep quantity and/or quality in a submarine environment. We propose that the unique submarine environment and the unique caffeine consumption patterns of submariners should be considered in the development of potential countermeasures for sleepiness.
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Affiliation(s)
- Sarah Chabal
- Naval Submarine Medical Research Laboratory, Groton, Connecticut, USA
- Leidos, Inc., Reston, Virginia, USA
- Sleep, Tactical Efficiency, and Endurance Laboratory, Warfighter Performance Department, Naval Health Research Center, San Diego, California, USA
| | - Jonathan R Folstein
- Naval Submarine Medical Research Laboratory, Groton, Connecticut, USA
- Leidos, Inc., Reston, Virginia, USA
| | - Evan D Chinoy
- Leidos, Inc., Reston, Virginia, USA
- Sleep, Tactical Efficiency, and Endurance Laboratory, Warfighter Performance Department, Naval Health Research Center, San Diego, California, USA
| | - Rachel R Markwald
- Sleep, Tactical Efficiency, and Endurance Laboratory, Warfighter Performance Department, Naval Health Research Center, San Diego, California, USA
| | - Harris R Lieberman
- US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
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Processing RGB Color Sensors for Measuring the Circadian Stimulus of Artificial and Daylight Light Sources. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12031132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The three main tasks of modern lighting design are to support the visual performance, satisfy color emotion (color quality), and promote positive non-visual outcomes. In view of large-scale applications, the use of simple and inexpensive RGB color sensors to monitor related visual and non-visual illumination parameters seems to be of great promise for the future development of human-centered lighting control systems. In this context, the present work proposes a new methodology to assess the circadian effectiveness of the prevalent lighting conditions for daylight and artificial light sources in terms of the physiologically relevant circadian stimulus (CS) metric using such color sensors. In the case of daylight, the raw sensor readouts were processed in such a way that the CIE daylight model can be applied as an intermediate step to estimate its spectral composition, from which CS can eventually be calculated straightforwardly. Maximal CS prediction errors of less than 0.0025 were observed when tested on real data. For artificial light sources, on the other hand, the CS approximation method of Truong et al. was applied to estimate its circadian effectiveness from the sensor readouts. In this case, a maximal CS prediction error of 0.028 must be reported, which is considerably larger compared to daylight, but still in an acceptable range for typical indoor lighting applications. The use of RGB color sensors is thus shown to be suitable for estimating the circadian effectiveness of both types of illumination with sufficient accuracy for practical applications.
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Measurement of Circadian Effectiveness in Lighting for Office Applications. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11156936] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
As one factor among others, circadian effectiveness depends on the spatial light distribution of the prevalent lighting conditions. In a typical office context focusing on computer work, the light that is experienced by the office workers is usually composed of a direct component emitted by the room luminaires and the computer monitors as well as by an indirect component reflected from the walls, surfaces, and ceiling. Due to this multi-directional light pattern, spatially resolved light measurements are required for an adequate prediction of non-visual light-induced effects. In this work, we therefore propose a novel methodological framework for spatially resolved light measurements that allows for an estimate of the circadian effectiveness of a lighting situation for variable field of view (FOV) definitions. Results of exemplary in-field office light measurements are reported and compared to those obtained from standard spectral radiometry to validate the accuracy of the proposed approach. The corresponding relative error is found to be of the order of 3–6%, which denotes an acceptable range for most practical applications. In addition, the impact of different FOVs as well as non-zero measurement angles will be investigated.
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Nie J, Zhou T, Chen Z, Dang W, Jiao F, Zhan J, Chen Y, Chen Y, Pan Z, Kang X, Wang Y, Wang Q, Tang Y, Dong W, Zhou S, Ma Y, Yu X, Zhang G, Shen B. The effects of dynamic daylight-like light on the rhythm, cognition, and mood of irregular shift workers in closed environment. Sci Rep 2021; 11:13059. [PMID: 34158564 PMCID: PMC8219698 DOI: 10.1038/s41598-021-92438-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 06/10/2021] [Indexed: 02/05/2023] Open
Abstract
Shift workers are mostly suffered from the disruption of circadian rhythm and health problems. In this study, we designed proper light environment to maintain stable circadian rhythm, cognitive performance, and mood status of shift workers. We used five-channel light-emitting diodes to build up the dynamic daylight-like light environment. The illuminance, correlated color temperature, and circadian action factor of light were tunable in the ranges of 226 to 678 lx, 2680 to 7314 K, and 0.32 to 0.96 throughout the day (5:30 to 19:40). During the nighttime, these parameters maintained about 200 lx, 2700 K, and 0.32, respectively. In this light environment, three subjects had engaged in shift work for 38 consecutive days. We measured plasma melatonin, activity counts, continuous performance tests, and visual analogue scale on mood to assess the rhythm, cognitive performance, and mood of subjects. After 38-day shift work, the subjects' peak melatonin concentration increased significantly. Their physiological and behavioral rhythms maintained stable. Their cognitive performance improved significantly after night work, compared with that before night work. Their mood status had no significant change during the 38-day shift work. These results indicated that the light environment was beneficial to maintain circadian rhythm, cognitive performance and mood status during long-term shift work in closed environment.
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Affiliation(s)
- Jingxin Nie
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 209, Chengfu Road, Haidian District, Beijing, 100871, China
| | - Tianhang Zhou
- Peking University Sixth Hospital, Peking University Institute of Mental Health, Key Laboratory of Mental Health, Ministry of Health (Peking University), Haidian District, 51, Huayuan North Road, Beijing, 100191, China
| | - Zhizhong Chen
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 209, Chengfu Road, Haidian District, Beijing, 100871, China.
| | - Weimin Dang
- Peking University Sixth Hospital, Peking University Institute of Mental Health, Key Laboratory of Mental Health, Ministry of Health (Peking University), Haidian District, 51, Huayuan North Road, Beijing, 100191, China.
| | - Fei Jiao
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 209, Chengfu Road, Haidian District, Beijing, 100871, China
- State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing, 100871, China
| | - Jinglin Zhan
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 209, Chengfu Road, Haidian District, Beijing, 100871, China
| | - Yifan Chen
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 209, Chengfu Road, Haidian District, Beijing, 100871, China
| | - Yiyong Chen
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 209, Chengfu Road, Haidian District, Beijing, 100871, China
| | - Zuojian Pan
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 209, Chengfu Road, Haidian District, Beijing, 100871, China
| | - Xiangning Kang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 209, Chengfu Road, Haidian District, Beijing, 100871, China
| | - Yongzhi Wang
- Dongguan Institute of Optoelectronics, Peking University, Dongguan, 523808, Guangdong, China
| | - Qi Wang
- Dongguan Institute of Optoelectronics, Peking University, Dongguan, 523808, Guangdong, China
| | - Yan Tang
- Department of Physical Education, Peking University, Beijing, 100871, China
| | - Wentian Dong
- Peking University Sixth Hospital, Peking University Institute of Mental Health, Key Laboratory of Mental Health, Ministry of Health (Peking University), Haidian District, 51, Huayuan North Road, Beijing, 100191, China
| | - Shuzhe Zhou
- Peking University Sixth Hospital, Peking University Institute of Mental Health, Key Laboratory of Mental Health, Ministry of Health (Peking University), Haidian District, 51, Huayuan North Road, Beijing, 100191, China
| | - Yantao Ma
- Peking University Sixth Hospital, Peking University Institute of Mental Health, Key Laboratory of Mental Health, Ministry of Health (Peking University), Haidian District, 51, Huayuan North Road, Beijing, 100191, China
| | - Xin Yu
- Peking University Sixth Hospital, Peking University Institute of Mental Health, Key Laboratory of Mental Health, Ministry of Health (Peking University), Haidian District, 51, Huayuan North Road, Beijing, 100191, China
| | - Guoyi Zhang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 209, Chengfu Road, Haidian District, Beijing, 100871, China
- Dongguan Institute of Optoelectronics, Peking University, Dongguan, 523808, Guangdong, China
| | - Bo Shen
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, 209, Chengfu Road, Haidian District, Beijing, 100871, China
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Nieuwenhuys A, Dora J, Knufinke-Meyfroyt M, Beckers D, Rietjens G, Helmhout P. "20,000 leagues under the sea": Sleep, cognitive performance, and self-reported recovery status during a 67-day military submarine mission. APPLIED ERGONOMICS 2021; 91:103295. [PMID: 33130453 DOI: 10.1016/j.apergo.2020.103295] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 09/07/2020] [Accepted: 10/21/2020] [Indexed: 06/11/2023]
Abstract
Employing a field-based monitoring paradigm, the current study examined day-to-day fluctuations in actigraphy-based sleep recordings, cognitive performance (10-min psychomotor vigilance test; PVT), and self-reported recovery status among 14 submariners throughout a 67-day military mission. Mission averages reflected suboptimal sleep that was of short overall duration (5:46 ± 1:29 h per 24-h day) and relatively low efficiency (82.5 ± 9.9%); suboptimal levels of cognitive performance (PVT mRT = 283 ± 35 ms; PVT response errors = 5.3 ± 4.8); and moderate levels of self-reported recovery. Whilst self-reported recovery status remained stable across mission days, small but consistent day-to-day increases in sleep onset latency and PVT mRT accumulated to reflect meaningful deterioration in sleep and cognitive performance across the entire 67-day mission (i.e., 47% and 16% of the overall mission average, respectively). Future work is required to corroborate the current findings, firmly establish underlying causes, and make evidence-based suggestions for interventions to improve and uphold submariners' health and performance.
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Affiliation(s)
- Arne Nieuwenhuys
- Department of Exercise Sciences, University of Auckland, Auckland, New Zealand; Behavioural Science Institute, Radboud University, Nijmegen, the Netherlands.
| | - Jonas Dora
- Behavioural Science Institute, Radboud University, Nijmegen, the Netherlands
| | - Melanie Knufinke-Meyfroyt
- Behavioural Science Institute, Radboud University, Nijmegen, the Netherlands; Philips Experience Design, Eindhoven, the Netherlands
| | - Debby Beckers
- Behavioural Science Institute, Radboud University, Nijmegen, the Netherlands
| | - Gerard Rietjens
- Training Medicine and Training Physiology, Army Command, Directory of Personnel, Royal Netherlands Army, Utrecht, the Netherlands; Department of Human Physiology and Sports Medicine, Vrije Universiteit Brussel, Brussels, Belgium
| | - Pieter Helmhout
- Training Medicine and Training Physiology, Army Command, Directory of Personnel, Royal Netherlands Army, Utrecht, the Netherlands
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Harrison EM, Schmied EA, Yablonsky AM, Glickman GL. Implementation of interventions designed to promote healthy sleep and circadian rhythms in shiftworkers. Chronobiol Int 2020; 38:467-479. [PMID: 33327802 DOI: 10.1080/07420528.2020.1845190] [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: 10/22/2022]
Abstract
Shiftwork is a significant risk factor for a host of negative health and safety outcomes, which have been at least partly attributed to disturbances of the circadian timing system. As a result, an entire sub-field of chronobiology has been devoted to developing and evaluating countermeasures for circadian misalignment, sleep disruption, fatigue, and other issues associated with shiftwork. Much of this research takes place under highly controlled laboratory conditions due to the necessity of accurately characterizing individual rhythms, both for intervention design and assessment of efficacy. Applied studies of interventions for shiftworkers are, by their nature, more complicated, often demonstrating less consistent findings. While this, in part, reflects execution under less rigorously controlled conditions, it may also stem from variability in implementation approaches. A systematic review of published studies (through May 2017) of interventions designed to enhance circadian health in shiftworkers was conducted to determine the frequency and quality of the assessment of implementation as well as barriers and enablers to implementation. A search of PubMed, PsychINFO, Web of Science, and CINAHL databases yielded a total of 5368 unique references. After a title and abstract screen, 323 proceeded to full-text review; 68 of those met final criteria for data extraction. Implementation was assessed to some degree in 60.3% of those 68 articles. Where it was assessed, the mean quality score on a scale from 1 to 5 (1 = very little, 3 = moderate, 5 = very in-depth) was 2.56. One or more enablers were identified in just 17 of the 68 studies (25.0%), and barriers in just 18 (26.5%). Implementation of these interventions is a critical but seldom-acknowledged component of their uptake and effectiveness, and we highly recommend that future shiftworker intervention research make an effort to incorporate formalized assessments of implementation and/or hybrid effectiveness-implementation approaches.
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Affiliation(s)
- Elizabeth M Harrison
- Center for Circadian Biology, University of California San Diego, La Jolla, CA, USA.,Leidos, Inc., San Diego, CA, USA.,Health and Behavioral Sciences Department, Naval Health Research Center, San Diego, CA, USA
| | - Emily A Schmied
- Leidos, Inc., San Diego, CA, USA.,Health and Behavioral Sciences Department, Naval Health Research Center, San Diego, CA, USA.,School of Public Health, San Diego State University, San Diego, CA, USA
| | - Abigail M Yablonsky
- Health and Behavioral Sciences Department, Naval Health Research Center, San Diego, CA, USA.,Directorate for Professional Education, Naval Medical Center San Diego, San Diego, CA, USA
| | - Gena L Glickman
- Center for Circadian Biology, University of California San Diego, La Jolla, CA, USA.,Department of Psychiatry and Neuroscience, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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11
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Figueiro MG, Pedler D. Red light: A novel, non-pharmacological intervention to promote alertness in shift workers. JOURNAL OF SAFETY RESEARCH 2020; 74:169-177. [PMID: 32951780 PMCID: PMC8059068 DOI: 10.1016/j.jsr.2020.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 03/23/2020] [Accepted: 06/23/2020] [Indexed: 06/11/2023]
Abstract
INTRODUCTION Night work requires inversion of the natural, diurnal human activity-rest cycle and is associated with decreased alertness and some measures of performance, reduced safety, adverse health effects, and chronic disruption of the melatonin cycle that has been associated with increased risk for several major diseases. Previous studies show that red light exposures at night can promote alertness and improve performance while not negatively affecting melatonin secretion. METHOD This ongoing crossover, mixed (within- and between-subjects) design field study is testing the efficacy and acceptance of red light delivered to day-shift and night-shift workers using personal light glasses while they are at work. Each participant experienced three lighting interventions at the eyes: red light (50 lx, 630 nm, the treatment intervention), blue light (50 lx, 460 nm, the positive control intervention), and dim white light (10 lx, 3,000 K, the placebo control). During the interventions, participants underwent visual performance testing, submitted salivary melatonin and cortisol samples, and provided subjective reports of sleepiness, sleep disturbance, and general health over the 20-week protocol. Due to the ongoing nature of the study, only the performance and subjective reports are presented here. RESULTS Preliminary results indicate that response times were improved by the red and blue interventions, but not accuracy and hit rates. Blue light was associated with improvements to self-reported sleep disturbances compared to dim light. CONCLUSIONS These field results partially support our laboratory results that showed a positive effect of red light for promoting alertness and certain performance outcomes during the day and at night. Practical Applications: Red light may be used to improve response times in shift workers. Continued research will elucidate the lighting interventions' effects on melatonin and objective sleep measures (actigraphy).
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Affiliation(s)
- Mariana G Figueiro
- Lighting Research Center, Rensselaer Polytechnic Institute, 21 Union Street, Troy, NY 12280, United States.
| | - David Pedler
- Lighting Research Center, Rensselaer Polytechnic Institute, 21 Union Street, Troy, NY 12280, United States
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12
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Nie J, Zhou T, Chen Z, Dang W, Jiao F, Zhan J, Chen Y, Chen Y, Pan Z, Kang X, Wang Y, Wang Q, Dong W, Zhou S, Yu X, Zhang G, Shen B. Investigation on entraining and enhancing human circadian rhythm in closed environments using daylight-like LED mixed lighting. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 732:139334. [PMID: 32438188 DOI: 10.1016/j.scitotenv.2020.139334] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/08/2020] [Accepted: 05/08/2020] [Indexed: 06/11/2023]
Abstract
Humans can undergo circadian disruption and misalignment when living in closed environments without sufficient daylight. Therefore, it is of great significance to investigate the effects of artificial light on the circadian rhythm. In this work, the red, green, blue, warm white, and cool white (RGBWW) five-channel light-emitting diodes (LEDs) were fabricated as the only light sources in the closed environment. The LED mixed lighting showed a high color rendering index (CRI) all the time. During the day, the light simulated the daylight and increased the tunability of the circadian action factor (CAF) and correlated color temperature (CCT). At night, it maintained low CAF and CCT. Three subjects did irregular shift work in the closed environment for 38 days. Their plasma melatonin and daily activity were measured to assess the circadian rhythm. After 38 days, the subjects' peak melatonin times did not shift significantly (p = 0.676), while their peak melatonin concentrations increased apparently (p = 0.005). The start times of the least active 5-h period (L5) in one day fluctuated in a small range. The standard deviation (SD) was <15.11 min in most times. These results demonstrated that the subjects' rhythms maintained stable and were enhanced. The periods of circular cross-correlation between activity and CAF oscillated around 24 h (SD = 15.4 min), indicating the entrainment of light on the stable 24-h rhythm. It was concluded that the daylight-like LED lighting effectively entrained and enhanced the circadian rhythm in the closed environment.
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Affiliation(s)
- Jingxin Nie
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Tianhang Zhou
- Peking University Sixth Hospital, Peking University Institute of Mental Health, Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing 100191, China
| | - Zhizhong Chen
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
| | - Weimin Dang
- Peking University Sixth Hospital, Peking University Institute of Mental Health, Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing 100191, China
| | - Fei Jiao
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China; State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China
| | - Jinglin Zhan
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Yifan Chen
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Yiyong Chen
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Zuojian Pan
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Xiangning Kang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Yongzhi Wang
- Dongguan Institute of Optoelectronics, Peking University, Dongguan 523808, Guangdong, China
| | - Qi Wang
- Dongguan Institute of Optoelectronics, Peking University, Dongguan 523808, Guangdong, China
| | - Wentian Dong
- Peking University Sixth Hospital, Peking University Institute of Mental Health, Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing 100191, China
| | - Shuzhe Zhou
- Peking University Sixth Hospital, Peking University Institute of Mental Health, Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing 100191, China
| | - Xin Yu
- Peking University Sixth Hospital, Peking University Institute of Mental Health, Key Laboratory of Mental Health, Ministry of Health (Peking University), Beijing 100191, China
| | - Guoyi Zhang
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China; Dongguan Institute of Optoelectronics, Peking University, Dongguan 523808, Guangdong, China
| | - Bo Shen
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
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Guo JH, Ma XH, Ma H, Zhang Y, Tian ZQ, Wang X, Shao YC. Circadian misalignment on submarines and other non-24-h environments - from research to application. Mil Med Res 2020; 7:39. [PMID: 32814592 PMCID: PMC7437048 DOI: 10.1186/s40779-020-00268-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 08/10/2020] [Indexed: 11/10/2022] Open
Abstract
Circadian clocks have important physiological and behavioral functions in humans and other organisms, which enable organisms to anticipate and respond to periodic environmental changes. Disturbances in circadian rhythms impair sleep, metabolism, and behavior. People with jet lag, night workers and shift workers are vulnerable to circadian misalignment. In addition, non-24-h cycles influence circadian rhythms and cause misalignment and disorders in different species, since these periods are beyond the entrainment ranges. In certain special conditions, e.g., on submarines and commercial ships, non-24-h watch schedules are often employed, which have also been demonstrated to be deleterious to circadian rhythms. Personnel working under such conditions suffer from circadian misalignment with their on-watch hours, leading to increased health risks and decreased cognitive performance. In this review, we summarize the research progress and knowledge concerning circadian rhythms on submarines and other environments in which non-24-h watch schedules are employed.
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Affiliation(s)
- Jin-Hu Guo
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006, China.
| | - Xiao-Hong Ma
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Huan Ma
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Yin Zhang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510006, China
| | - Zhi-Qiang Tian
- China Institute of Marine Technology and Economy, Beijing, 100081, China
| | - Xin Wang
- China Institute of Marine Technology and Economy, Beijing, 100081, China
| | - Yong-Cong Shao
- School of Psychology, Beijing Sport University, Beijing, 100084, China
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14
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Zhao P, Wang Q, Kaur M, Kim YI, Dewald HD, Mozziconacci O, Liu Y, Chen H. Absolute Quantitation of Proteins by Coulometric Mass Spectrometry. Anal Chem 2020; 92:7877-7883. [DOI: 10.1021/acs.analchem.0c01151] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Pengyi Zhao
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States,
| | - Qi Wang
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States,
| | - Manpreet Kaur
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States,
| | - Yong-Ick Kim
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States,
| | - Howard D. Dewald
- Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States
| | - Olivier Mozziconacci
- Department of Analytical Sciences, Merck Research Laboratories, Merck &Co., Inc., Rahway, New Jersey 07065, United States
| | - Yong Liu
- Department of Analytical Sciences, Merck Research Laboratories, Merck &Co., Inc., Rahway, New Jersey 07065, United States
| | - Hao Chen
- Department of Chemistry & Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States,
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Nagare R, Rea MS, Plitnick B, Figueiro MG. Nocturnal Melatonin Suppression by Adolescents and Adults for Different Levels, Spectra, and Durations of Light Exposure. J Biol Rhythms 2019; 34:178-194. [PMID: 30803301 DOI: 10.1177/0748730419828056] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The human circadian system is primarily regulated by the 24-h LD cycle incident on the retina, and nocturnal melatonin suppression is a primary outcome measure for characterizing the biological clock's response to those light exposures. A limited amount of data related to the combined effects of light level, spectrum, and exposure duration on nocturnal melatonin suppression has impeded the development of circadian-effective lighting recommendations and light-treatment methods. The study's primary goal was to measure nocturnal melatonin suppression for a wide range of light levels (40 to 1000 lux), 2 white light spectra (2700 K and 6500 K), and an extended range of nighttime light exposure durations (0.5 to 3.0 h). The study's second purpose was to examine whether differences existed between adolescents' and adults' circadian sensitivity to these lighting characteristics. The third purpose was to provide an estimate of the absolute threshold for the impact of light on acute melatonin suppression. Eighteen adolescents (age range, 13 to 18 years) and 23 adults (age range, 24 to 55 years) participated in the study. Results showed significant main effects of light level, spectrum, and exposure duration on melatonin suppression. Moreover, the data also showed that the relative suppressing effect of light on melatonin diminishes with increasing exposure duration for both age groups and both spectra. The present results do not corroborate our hypothesis that adolescents exhibit greater circadian sensitivity to short-wavelength radiation compared with adults. As for threshold, it takes longer to observe significant melatonin suppression at lower CS levels than at higher CS levels. Dose-response curves (amount and duration) for both white-light spectra and both age groups can guide lighting recommendations when considering circadian-effective light in applications such as offices, schools, residences, and healthcare facilities.
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Affiliation(s)
- Rohan Nagare
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Mark S Rea
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Barbara Plitnick
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Mariana G Figueiro
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY, USA
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Figueiro MG, Sahin L, Roohan C, Kalsher M, Plitnick B, Rea MS. Effects of red light on sleep inertia. Nat Sci Sleep 2019; 11:45-57. [PMID: 31118850 PMCID: PMC6506010 DOI: 10.2147/nss.s195563] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 03/08/2019] [Indexed: 11/23/2022] Open
Abstract
Introduction: Sleep inertia, broadly defined as decrements in performance and lowering of alertness following waking, lasts for durations ranging between 1 min and 3 hrs. This study investigated whether, compared to a dim light condition (the control), exposure to long-wavelength (red) light delivered to closed eyelids during sleep (red light mask) and to eyes open upon waking (red light goggles) reduced sleep inertia. Methods: Thirty participants (18 females, 12 males; mean age=30.4 years [SD 13.7]) completed this crossover, within-subjects, counterbalanced design study. Self-reported measures of sleepiness and objective measures of auditory performance and cortisol levels were collected on 3 Friday nights over the course of 3 consecutive weeks. Results: Performance improved significantly during the 30-min data collection period in all experimental conditions. Subjective sleepiness also decreased significantly with time awake in all experimental conditions. As hypothesized, performance of some tasks was significantly better in the red light mask condition than in the dim light condition. Performance scores in the red light goggles condition improved significantly after a few minutes of wearing the light goggles. Discussion: The results show that saturated red light delivered through closed eyelids at levels that do not suppress melatonin can be used to mitigate sleep inertia upon waking.
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Affiliation(s)
- Mariana G Figueiro
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Levent Sahin
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Charles Roohan
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Michael Kalsher
- Department of Cognitive Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Barbara Plitnick
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Mark S Rea
- Lighting Research Center, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
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Valdimarsdottir HB, Figueiro MG, Holden W, Lutgendorf S, Wu LM, Ancoli‐Israel S, Chen J, Hoffman‐Peterson A, Granski J, Prescott N, Vega A, Stern N, Winkel G, Redd WH. Programmed environmental illumination during autologous stem cell transplantation hospitalization for the treatment of multiple myeloma reduces severity of depression: A preliminary randomized controlled trial. Cancer Med 2018; 7:4345-4353. [PMID: 30099857 PMCID: PMC6144249 DOI: 10.1002/cam4.1690] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 05/31/2018] [Accepted: 06/16/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Over a third of multiple myeloma (MM) patients report clinical levels of depression during autologous stem cell transplant (ASCT) hospitalization. We report preliminary results from a randomized clinical trial investigating the effect of Programmed Environmental Illumination (PEI) of hospital rooms on depression. METHODS Patients (N = 187) scheduled to receive an ASCT were assessed for eligibility. Those who met study eligibility criteria (n = 44) were randomly assigned to one of two PEI conditions involving delivery of either circadian active bright white light (BWL) or circadian inactive dim white light (DWL) throughout the room from 7 to 10 am daily during hospitalization. Patients completed the Center for Epidemiological Studies Depression Scale (CES-D) prior to hospitalization, at days 2 and 7 post-transplant, and on the third day of engraftment. RESULTS General linear model analyses revealed no difference between the groups in CES-D total score at baseline (P = 0.7859). A longitudinal linear mixed model analysis revealed a significant interaction between time of assessment and light condition [F(3,107) = 2.90; P = 0.0386; ɳ2 = 0.08)], indicating that PEI prevented the development of depression during hospitalization, with effects reaching significance by the third day of engraftment. At the third day of engraftment, 68.4% of the participants in the DWL comparison condition met the criteria for clinically significant depression compared to 42.1% in the BWL condition. CONCLUSION These findings demonstrate that PEI using BWL during MM ASCT hospitalization is effective in reducing the development of depression. Future studies should examine the mechanisms whereby PEI improves depression.
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Affiliation(s)
- Heiðdís B. Valdimarsdottir
- PsychologyReykjavik UniversityReykjavikIceland
- Population Health Science and PolicyIcahn School of Medicine at Mount SinaiNew York CityNew York
| | | | - William Holden
- Population Health Science and PolicyIcahn School of Medicine at Mount SinaiNew York CityNew York
| | - Susan Lutgendorf
- Departments of Psychology and Brain Sciences, Obstetrics and Gynecology, and UrologyUniversity of Iowa College of Liberal Arts and SciencesIowa CityIowa
| | - Lisa M. Wu
- Department of Medical Social SciencesNorthwestern University Feinberg School of MedicineChicagoIllinois
| | - Sonia Ancoli‐Israel
- Department of PsychiatryUniversity of California San DiegoLa JollaCalifornia
| | - Jason Chen
- Population Health Science and PolicyIcahn School of Medicine at Mount SinaiNew York CityNew York
| | - Ariella Hoffman‐Peterson
- Population Health Science and PolicyIcahn School of Medicine at Mount SinaiNew York CityNew York
| | - Julia Granski
- Population Health Science and PolicyIcahn School of Medicine at Mount SinaiNew York CityNew York
| | - Nina Prescott
- Population Health Science and PolicyIcahn School of Medicine at Mount SinaiNew York CityNew York
| | - Alejandro Vega
- Population Health Science and PolicyIcahn School of Medicine at Mount SinaiNew York CityNew York
| | - Natalie Stern
- Population Health Science and PolicyIcahn School of Medicine at Mount SinaiNew York CityNew York
| | - Gary Winkel
- Population Health Science and PolicyIcahn School of Medicine at Mount SinaiNew York CityNew York
| | - William H. Redd
- Population Health Science and PolicyIcahn School of Medicine at Mount SinaiNew York CityNew York
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18
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The impact of daytime light exposures on sleep and mood in office workers. Sleep Health 2017; 3:204-215. [PMID: 28526259 DOI: 10.1016/j.sleh.2017.03.005] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 03/09/2017] [Accepted: 03/15/2017] [Indexed: 12/20/2022]
Abstract
BACKGROUND By affecting the internal timing mechanisms of the brain, light regulates human physiology and behavior, perhaps most notably the sleep-wake cycle. Humans spend over 90% of their waking hours indoors, yet light in the built environment is not designed to affect circadian rhythms. OBJECTIVE Using a device calibrated to measure light that is effective for the circadian system (circadian-effective light), collect personal light exposures in office workers and relate them to their sleep and mood. SETTING The research was conducted in 5 buildings managed by the US General Services Administration. PARTICIPANTS This study recruited 109 participants (69 females), of whom 81 (54 females) participated in both winter and summer. MEASUREMENTS Self-reported measures of mood and sleep, and objective measures of circadian-effective light and activity rhythms were collected for 7 consecutive days. RESULTS Compared to office workers receiving low levels of circadian-effective light in the morning, receiving high levels in the morning is associated with reduced sleep onset latency (especially in winter), increased phasor magnitudes (a measure of circadian entrainment), and increased sleep quality. High levels of circadian-effective light during the entire day are also associated with increased phasor magnitudes, reduced depression, and increased sleep quality. CONCLUSIONS The present study is the first to measure personal light exposures in office workers using a calibrated device that measures circadian-effective light and relate those light measures to mood, stress, and sleep. The study's results underscore the importance of daytime light exposures for sleep health.
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Caddick ZA, Gregory K, Flynn-Evans EE. Sleep Environment Recommendations for Future Spaceflight Vehicles. ADVANCES IN INTELLIGENT SYSTEMS AND COMPUTING 2017. [DOI: 10.1007/978-3-319-41682-3_76] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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