Records |
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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English |
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2090-3553 |
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PMID:23471148; PMCID:PMC3581131 |
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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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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 |
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English |
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ISSN |
1389-9457 |
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Notes |
PMID:18805055; PMCID:PMC2723863 |
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no |
Call Number |
IDA @ john @ |
Serial |
289 |
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Author |
Peixoto, C.A.T.; da Silva, A.G.T.; Carskadon, M.A.; Louzada, F.M. |
Title |
Adolescents living in homes without electric lighting have earlier sleep times |
Type |
Journal Article |
Year  |
2009 |
Publication |
Behavioral Sleep Medicine |
Abbreviated Journal |
Behav Sleep Med |
Volume |
7 |
Issue |
2 |
Pages |
73-80 |
Keywords |
Human Health; Sleep |
Abstract |
The aim of this project was to compare circadian rhythmicity of a group of 37 adolescents (14 girls), aged 11 to 16 (mean age = 13.1 +/- 1.7 years), with and without electricity at home. Twenty students attended morning school (07:30-11:30), and 17 attended evening school classes (19:00-22:30). Eleven adolescents had no electric lighting at home (5 attended morning classes and 6 attended evening classes). They completed a sleep log and wore a wrist actigraph for 5 consecutive days. Saliva samples were collected to assess DLMO. Data were compared by ANOVA and showed later timing and a more extended sleep period for those who attended late classes. Those adolescents without electricity at home had significantly earlier sleep onset on school days. As to DLMO, a trend to a delay was observed in the groups who had electric lighting. |
Address |
Department of Physiology, Universidade Federal do Parana, Brazil. pedatardelli@yahoo.com.br |
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English |
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1540-2002 |
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PMID:19330580 |
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Call Number |
LoNNe @ kyba @ |
Serial |
1481 |
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