Records |
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 |
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ISSN |
1389-9457 |
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PMID:21704557; PMCID:PMC3145013 |
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no |
Call Number |
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 |
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0161-8105 |
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PMID:21886359; PMCID:PMC3157663 |
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no |
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IDA @ john @ |
Serial |
344 |
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Author |
Mottram, V.; Middleton, B.; Williams, P.; Arendt, J. |
Title |
The impact of bright artificial white and 'blue-enriched' light on sleep and circadian phase during the polar winter |
Type |
Journal Article |
Year  |
2011 |
Publication |
Journal of Sleep Research |
Abbreviated Journal |
J Sleep Res |
Volume |
20 |
Issue |
1 Pt 2 |
Pages |
154-161 |
Keywords |
Adult; Circadian Rhythm/*physiology; *Cold Climate; Female; Humans; *Light; Male; Medical Records; Questionnaires; Sleep/*physiology; Time Factors; blue light |
Abstract |
Delayed sleep phase (and sometimes free-run) is common in the Antarctic winter (no natural sunlight) and optimizing the artificial light conditions is desirable. This project evaluated sleep when using 17,000 K blue-enriched lamps compared with standard white lamps (5000 K) for personal and communal illumination. Base personnel, 10 males, five females, 32.5+/-8 years took part in the study. From 24 March to 21 September 2006 light exposure alternated between 4-5-week periods of standard white (5000 K) and blue-enriched lamps (17,000 K), with a 3-week control before and after extra light. Sleep and light exposure were assessed by actigraphy and sleep diaries. General health (RAND 36-item questionnaire) and circadian phase (urinary 6-sulphatoxymelatonin rhythm) were evaluated at the end of each light condition. Direct comparison (rmanova) of blue-enriched light with white light showed that sleep onset was earlier by 19 min (P=0.022), and sleep latency tended to be shorter by 4 min (P=0.065) with blue-enriched light. Analysing all light conditions, control, blue and white, again provided evidence for greater efficiency of blue-enriched light compared with white (P<0.05), but with the best sleep timing, duration, efficiency and quality in control natural light conditions. Circadian phase was earlier on average in midwinter blue compared with midwinter white light by 45 min (P<0.05). Light condition had no influence on general health. We conclude that the use of blue-enriched light had some beneficial effects, notably earlier sleep, compared with standard white light during the polar winter. |
Address |
British Antarctic Survey Medical Unit, Derriford Hospital, Plymouth, UK |
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English |
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ISSN |
0962-1105 |
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PMID:20723022 |
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no |
Call Number |
IDA @ john @ |
Serial |
348 |
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Author |
Escobar, C.; Salgado-Delgado, R.; Gonzalez-Guerra, E.; Tapia Osorio, A.; Angeles-Castellanos, M.; Buijs, R.M. |
Title |
Circadian disruption leads to loss of homeostasis and disease |
Type |
Journal Article |
Year  |
2011 |
Publication |
Sleep Disorders |
Abbreviated Journal |
Sleep Disord |
Volume |
2011 |
Issue |
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Pages |
964510 |
Keywords |
Human Health |
Abstract |
The relevance of a synchronized temporal order for adaptation and homeostasis is discussed in this review. We present evidence suggesting that an altered temporal order between the biological clock and external temporal signals leads to disease. Evidence mainly based on a rodent model of “night work” using forced activity during the sleep phase suggests that altered activity and feeding schedules, out of phase from the light/dark cycle, may be the main cause for the loss of circadian synchrony and disease. It is proposed that by avoiding food intake during sleep hours the circadian misalignment and adverse consequences can be prevented. This review does not attempt to present a thorough revision of the literature, but instead it aims to highlight the association between circadian disruption and disease with special emphasis on the contribution of feeding schedules in circadian synchrony. |
Address |
Departamento de Anatomia, Facultad de Medicina, Universidad Nacional Autonoma de Mexico, 04360 Mexico City, DF, Mexico |
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2090-3553 |
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Notes |
PMID:23471148; PMCID:PMC3581131 |
Approved |
no |
Call Number |
LoNNe @ kagoburian @ |
Serial |
745 |
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Author |
Pereira, Ã.F.; Louzada, F.M.; Moreno, C.R.C. |
Title |
Not all adolescents are sleep deprived: A study of rural populations: Sleep duration in rural populations |
Type |
Journal Article |
Year  |
2010 |
Publication |
Sleep and Biological Rhythms |
Abbreviated Journal |
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Volume |
8 |
Issue |
4 |
Pages |
267-273 |
Keywords |
Human Health; Sleep |
Abstract |
The objective of this study was to investigate the role of environmental factors in sleep duration among adolescents living in rural areas. A total of 1140 students (569 males), aged 10â19 years, and attending two schools in rural regions in southern Brazil, completed a questionnaire about their sleep habits. Demographic data were also obtained. Prevalence ratios (PR) were estimated for the cases of more than 9 h of sleep on weekdays. Sleep duration in adolescents with and without electric lighting at home was analyzed. Average sleep duration at night was 9.63 (1.64) h on school-going days and 10.14 (2.42) h on weekends. The prevalence of adolescents sleeping for more than 9 h at night on school-going days was 58.3%. Older adolescents showed a tendency to delay their sleep onset times, which is associated with a reduction of sleep duration. Adolescents without electric lighting at home slept longer on school-going days (P < 0.001) and on weekends (P= 0.013) when compared to those with electric lighting at home. From multivariate analysis, age (P < 0.001), school schedule (P= 0.007) and work (0.042) were factors affecting sleep duration. In contrast to the data previously reported for urban populations, we found a high prevalence of adolescents sleeping for more than 9 h on school nights. Data on populations living in less industrialized regions reinforce the idea that technological advances are associated with the negative impact of sleep phase delay in adolescents. |
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1446-9235 |
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LoNNe @ kyba @ |
Serial |
1482 |
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