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Author Smith, M.R.; Eastman, C.I.
Title Shift work: health, performance and safety problems, traditional countermeasures, and innovative management strategies to reduce circadian misalignment Type Journal Article
Year 2012 Publication Nature and Science of Sleep Abbreviated Journal Nat Sci Sleep
Volume 4 Issue Pages 111-132
Keywords bright light; circadian rhythms; melatonin; night work; phase-shifting; sleep
Abstract There are three mechanisms that may contribute to the health, performance, and safety problems associated with night-shift work: (1) circadian misalignment between the internal circadian clock and activities such as work, sleep, and eating, (2) chronic, partial sleep deprivation, and (3) melatonin suppression by light at night. The typical countermeasures, such as caffeine, naps, and melatonin (for its sleep-promoting effect), along with education about sleep and circadian rhythms, are the components of most fatigue risk-management plans. We contend that these, while better than nothing, are not enough because they do not address the underlying cause of the problems, which is circadian misalignment. We explain how to reset (phase-shift) the circadian clock to partially align with the night-work, day-sleep schedule, and thus reduce circadian misalignment while preserving sleep and functioning on days off. This involves controlling light and dark using outdoor light exposure, sunglasses, sleep in the dark, and a little bright light during night work. We present a diagram of a sleep-and-light schedule to reduce circadian misalignment in permanent night work, or a rotation between evenings and nights, and give practical advice on how to implement this type of plan.
Address Biological Rhythms Research Laboratory, Rush University Medical Center, Chicago, IL, USA
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1179-1608 ISBN Medium
Area Expedition Conference
Notes PMID:23620685; PMCID:PMC3630978 Approved no
Call Number (up) IDA @ john @ Serial 149
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Author Haus, E.L.; Smolensky, M.H.
Title Shift work and cancer risk: potential mechanistic roles of circadian disruption, light at night, and sleep deprivation Type Journal Article
Year 2013 Publication Sleep Medicine Reviews Abbreviated Journal Sleep Med Rev
Volume 17 Issue 4 Pages 273-284
Keywords Cell Cycle/physiology; Circadian Rhythm/*physiology; Epigenesis, Genetic/physiology; Humans; Light; Melatonin/physiology; Neoplasms/*etiology; Risk Factors; Sleep Deprivation/*complications; Work Schedule Tolerance/*physiology; oncogenesis
Abstract Shift work that includes a nighttime rotation has become an unavoidable attribute of today's 24-h society. The related disruption of the human circadian time organization leads in the short-term to an array of jet-lag-like symptoms, and in the long-run it may contribute to weight gain/obesity, metabolic syndrome/type II diabetes, and cardiovascular disease. Epidemiologic studies also suggest increased cancer risk, especially for breast cancer, in night and rotating female shift workers. If confirmed in more controlled and detailed studies, the carcinogenic effect of night and shift work will constitute additional serious medical, economic, and social problems for a substantial proportion of the working population. Here, we examine the possible multiple and interconnected cancer-promoting mechanisms as a consequence of shift work, i.e., repeated disruption of the circadian system, pineal hormone melatonin suppression by exposure to light at night, sleep-deprivation-caused impairment of the immune system, plus metabolic changes favoring obesity and generation of proinflammatory reactive oxygen species.
Address Department of Laboratory Medicine & Pathology, University of Minnesota and Health Partners Medical Group, Regions Hospital, 640 Jackson Street, St. Paul, Minnesota 55101, USA. Erhard.X.Haus@HealthPartners.com
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1087-0792 ISBN Medium
Area Expedition Conference
Notes PMID:23137527 Approved no
Call Number (up) IDA @ john @ Serial 157
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Author Smith, M.R.; Revell, V.L.; Eastman, C.I.
Title Phase advancing the human circadian clock with blue-enriched polychromatic light Type Journal Article
Year 2009 Publication Sleep Medicine Abbreviated Journal Sleep Med
Volume 10 Issue 3 Pages 287-294
Keywords Adult; Circadian Rhythm/*radiation effects; Female; Humans; *Light; Lighting/*methods; Male; Melatonin/metabolism; Phototherapy/*methods; Sleep; Wakefulness; Young Adult; blue light; sleep
Abstract BACKGROUND: Previous studies have shown that the human circadian system is maximally sensitive to short-wavelength (blue) light. Whether this sensitivity can be utilized to increase the size of phase shifts using light boxes and protocols designed for practical settings is not known. We assessed whether bright polychromatic lamps enriched in the short-wavelength portion of the visible light spectrum could produce larger phase advances than standard bright white lamps. METHODS: Twenty-two healthy young adults received either a bright white or bright blue-enriched 2-h phase advancing light pulse upon awakening on each of four treatment days. On the first treatment day the light pulse began 8h after the dim light melatonin onset (DLMO), on average about 2h before baseline wake time. On each subsequent day, light treatment began 1h earlier than the previous day, and the sleep schedule was also advanced. RESULTS: Phase advances of the DLMO for the blue-enriched (92+/-78 min, n=12) and white groups (76+/-45 min, n=10) were not significantly different. CONCLUSION: Bright blue-enriched polychromatic light is no more effective than standard bright light therapy for phase advancing circadian rhythms at commonly used therapeutic light levels.
Address Biological Rhythms Research Laboratory, Rush University Medical Center, Suite 425, 1645 W. Jackson Boulevard, Chicago, IL 60612, USA
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1389-9457 ISBN Medium
Area Expedition Conference
Notes PMID:18805055; PMCID:PMC2723863 Approved no
Call Number (up) IDA @ john @ Serial 289
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Author Sharkey, K.M.; Carskadon, M.A.; Figueiro, M.G.; Zhu, Y.; Rea, M.S.
Title Effects of an advanced sleep schedule and morning short wavelength light exposure on circadian phase in young adults with late sleep schedules Type Journal Article
Year 2011 Publication Sleep Medicine Abbreviated Journal Sleep Med
Volume 12 Issue 7 Pages 685-692
Keywords Affect/physiology/radiation effects; Circadian Rhythm/*physiology/*radiation effects; Color; Dose-Response Relationship, Radiation; Female; Humans; *Light; Male; Melatonin/metabolism; Photoperiod; Phototherapy/*methods; Saliva/metabolism; Sleep/physiology/radiation effects; Sleep Disorders, Circadian Rhythm/prevention & control/*therapy; Stress, Psychological/prevention & control/therapy; Treatment Outcome; Young Adult; blue light
Abstract OBJECTIVE: We examined the effects of an advanced sleep/wake schedule and morning short wavelength (blue) light in 25 adults (mean age+/-SD=21.8+/-3 years; 13 women) with late sleep schedules and subclinical features of delayed sleep phase disorder (DSPD). METHODS: After a baseline week, participants kept individualized, fixed, advanced 7.5-h sleep schedules for 6days. Participants were randomly assigned to groups to receive “blue” (470nm, approximately 225lux, n=12) or “dim” (<1lux, n=13) light for 1h after waking each day. Head-worn “Daysimeters” measured light exposure; actigraphs and sleep diaries confirmed schedule compliance. Salivary dim light melatonin onset (DLMO), self-reported sleep, and mood were examined with 2x2 ANOVA. RESULTS: After 6days, both groups showed significant circadian phase advances, but morning blue light was not associated with larger phase shifts than dim-light exposure. The average DLMO advances (mean+/-SD) were 1.5+/-1.1h in the dim light group and 1.4+/-0.7h in the blue light group. CONCLUSIONS: Adherence to a fixed advanced sleep/wake schedule resulted in significant circadian phase shifts in young adults with subclinical DSPD with or without morning blue light exposure. Light/dark exposures associated with fixed early sleep schedules are sufficient to advance circadian phase in young adults.
Address Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, Alpert Medical School of Brown University, Box G-RIH, Providence, RI 02912, USA. katherine_sharkey@brown.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1389-9457 ISBN Medium
Area Expedition Conference
Notes PMID:21704557; PMCID:PMC3145013 Approved no
Call Number (up) IDA @ john @ Serial 303
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Author Kessel, L.; Siganos, G.; Jorgensen, T.; Larsen, M.
Title Sleep disturbances are related to decreased transmission of blue light to the retina caused by lens yellowing Type Journal Article
Year 2011 Publication Sleep Abbreviated Journal Sleep
Volume 34 Issue 9 Pages 1215-1219
Keywords Adult; Age Factors; Aging/*pathology/physiology; Circadian Rhythm/physiology; Cross-Sectional Studies; Female; Fluorometry; Humans; Lens, Crystalline/*pathology/physiopathology; *Light; Male; Middle Aged; Retina/*physiopathology; Risk Factors; *Scattering, Radiation; Sleep Disorders/*etiology; Circadian rhythm; cataract; melanopsin; sleep; blue light
Abstract STUDY OBJECTIVES: Sleep pattern and circadian rhythms are regulated via the retinohypothalamic tract in response to stimulation of a subset of retinal ganglion cells, predominantly by blue light (450-490 nm). With age, the transmission of blue light to the retina is reduced because of the aging process of the human lens, and this may impair the photoentrainment of circadian rhythm leading to sleep disorders. The aim of the study was to examine the association between lens aging and sleep disorders. DESIGN: Cross-sectional population based study. SETTING: The study was performed at the Research Center for Prevention and Health, Glostrup Hospital, Denmark and at the Department of Ophthalmology, Herlev Hospital, Denmark. PARTICIPANTS: An age- and sex-stratified sample of 970 persons aged 30 to 60 years of age drawn from a sample randomly selected from the background population. INTERVENTIONS: Not applicable. MEASUREMENTS AND RESULTS: Sleep disturbances were evaluated by a combination of questionnaire and the use of prescription sleeping medication. Lens aging (transmission and yellowing) was measured objectively by lens autofluorometry. The risk of sleep disturbances was significantly increased when the transmission of blue light to the retina was low, even after correction for the effect of age and other confounding factors such as smoking habits, diabetes mellitus, gender, and the risk of ischemic heart disease (P < 0.0001). CONCLUSIONS: Filtration of blue light by the aging lens was significantly associated with an increased risk of sleep disturbances. We propose that this is a result of disturbance of photoentrainment of circadian rhythms.
Address Department of Ophthalmology, Glostrup Hospital, University of Copenhagen, Denmark. line.kessel@dadlnet.dk
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0161-8105 ISBN Medium
Area Expedition Conference
Notes PMID:21886359; PMCID:PMC3157663 Approved no
Call Number (up) IDA @ john @ Serial 344
Permanent link to this record