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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
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 0962-1105 ISBN Medium
Area Expedition Conference
Notes PMID:20723022 Approved no
Call Number (up) IDA @ john @ Serial 348
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Author Kayaba, M.; Iwayama, K.; Ogata, H.; Seya, Y.; Tokuyama, K.; Satoh, M.
Title Drowsiness and low energy metabolism in the following morning induced by nocturnal blue light exposure Type Journal Article
Year 2013 Publication Sleep Medicine Abbreviated Journal Sleep Medicine
Volume 14 Issue Pages e166-e167
Keywords blue light; light exposure; light at night; circadian disruption; drowsiness; melatonin; metabolism; sleep
Abstract Introduction

Evening light exposure debilitates the circadian rhythm and elicits sleep disturbance. Blue light peak wavelengths, around 460 nm, suppress melatonin secretion via the non-image-forming system. The effects of nocturnal blue light exposure on sleep have been reported to be specific but rather small (Münch, 2008). This study was designed to assess the effect of nocturnal blue light exposure on sleep and energy metabolism until noon the next day.

Materials and methods

Nine healthy male volunteers aged between 21 and 25 participated in this study which had a balanced cross-over design with intrasubject comparisons. After 2 h dark adaptation, the subjects were exposed to blue light or no light for 2 h. The peak wavelength of the blue LED was 465 nm, and the horizontal irradiance of the blue light at the height of eye was at 7.02fÊW/cm2. Sleep was recorded polysomnographically, and energy metabolism was measured with a whole body indirect calorimeter.

Results

There were no significant differences in sleep architecture and energy metabolism during the night. However, dozing (stages 1 and 2) was significantly higher (26.0 < 29.4 vs 6.3 < 8.1 min, P < 0.05), and energy expenditure, O2 consumption, CO2 production and the thermic effect of food (increase in energy expenditure after breakfast) were significantly lower the following morning in the blue light exposure subjects.

Conclusion

Contrary to our expectation, sleep architecture and energy metabolism during sleep were not affected by evening exposure to blue light. It might be due to our milder intervention by which subjects in a sitting position did not gaze at the light source set on the ceiling, while the subjects in previous studies directly received brighter light via custom built goggles (Cajochen, 2005; Münch, 2008) or gazed at a light source under the influence of mydriatic agents to dilate pupils (Brainard, 2001). New findings of the present study were that dozing (stages 1 and 2) was significantly increased, and energy metabolism was significantly lower the following morning in blue light exposed subjects. This suggests that modulation of the circadian rhythm is affected by nocturnal blue light exposure and the effect continues in the following daytime even if the intervention was mild.
Address University of Tsukuba, Graduate School of Comprehensive Human Sciences, Japan
Corporate Author Thesis
Publisher Place of Publication Editor
Language 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 Approved no
Call Number (up) IDA @ john @ Serial 349
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Author Middleton, B.; Arendt, J.; Stone, BM
Title Human circadian rhythms in constant dim light (8 lux) with knowledge of clock time Type Journal Article
Year 1996 Publication Journal of Sleep Research Abbreviated Journal J. Sleep Res.
Volume 5 Issue 2 Pages 69-76
Keywords Human Health; circadian rhythm; light/dark cycle; melatonin; entrainment; melatonin levels; 6-sulphatoxymelatonin
Abstract The light/dark (L/D) cycle is a major synchronizer of human circadian rhythms. In the absence of a strong L/D cycle, synchrony with 24 hours can nevertheless be maintained in a socially structured environment, as shown in Polar regions (Broadway et al. 1987) and by some blind subjects (Czeisler et al. 1995a). The relative contribution of other time cues to entrainment in dim light has not been fully explored. The present study investigated the behaviour of melatonin (assessed as 6-sulphatoxymelatonin); rectal temperature; activity and sleep (actigraphy and logs) in constant dim light (L/ L) with access to a digital clock. 6 normal healthy males were maintained as a group in partial temporal isolation with attenuated sound and ambient temperature for 21 days. All 6 subjects showed free-running periodicity for 6-sulphatoxymelatonin and 5/6 subjects for temperature, activity and sleep offset. The average period (tau) was 24.26 +/- 0.049, substantially shorter than in previous experiments with a self selected L/D cycle but similar to a recent study conducted in very dim light. One subject maintained a rigid sleep/wake cycle throughout whilst his 6-sulphatoxymelatonin rhythm free-ran. Total sleep time, from actigraph data, did not change but sleep efficiency decreased during the experiment. The subjects did not show group synchronization. These results confirm previous data indicating the importance of the L/D cycle in human entrainment and underline the lesser role of social cues and knowledge of clock time. This particular approach will permit the administration of timed medication to sighted humans under free-running conditions.
Address
Corporate Author Thesis
Publisher Wiley Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number (up) IDA @ john @ Serial 1098
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Author Sletten, T.L.; Cappuccio, F.P.; Davidson, A.J.; Van Cauter, E.; Rajaratnam, S.M.W.; Scheer, F.A.J.L.
Title Health consequences of circadian disruption Type Journal Article
Year 2020 Publication Sleep Abbreviated Journal Sleep
Volume 43 Issue 1 Pages
Keywords Human Health; Circadian Rhythm; Chronobiology; Sleep; Review
Abstract The circadian system is key for optimal functioning by maintaining synchrony between internal circadian rhythms, behaviors, and external cues. Many clinicians are not fully aware, however, of the far-reaching implications of the circadian system for human health. Clinical attention to circadian rhythms has largely focused on sleep disturbances. The impact of the circadian system on health is, however, much broader. Clinical diagnoses are often based on single time point assessments during the day, ignoring circadian influences on physiology. Even when time is considered, using (external) clock time ignores the large interindividual differences in internal timing.
Address Division of Sleep Medicine, Harvard Medical School, Boston, MA
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:31930347 Approved no
Call Number (up) IDA @ john @ Serial 2822
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Author Komada, Y.; Aoki, K.; Gohshi, S.; Ichioka, H.; Shibata, S.
Title Effects of television luminance and wavelength at habitual bedtime on melatonin and cortisol secretion in humans: Blue light and melatonin secretion Type Journal Article
Year 2015 Publication Sleep and Biological Rhythms Abbreviated Journal Sleep and Biological Rhythms
Volume 13 Issue 4 Pages 316–322
Keywords Human Health
Abstract The aim of this study was to examine the effect of exposure to different types of television displays at habitual bedtime on human melatonin and cortisol secretion. Thirteen male participants (mean age: 22.7 ± 0.85 years) were tested over three nights in one baseline and two experimental sessions. Participants were instructed to watch a movie on four different luminance- and wavelength-controlled television displays: normal luminance (450 candela [cd]/m2) or high luminance (1200&#8201;cd/m2) and normal blue light or half blue light. Salivary melatonin and cortisol levels were measured at two time points before and after television viewing. There was no significant difference in cortisol secretion due to the different displays. Melatonin suppression was significantly lower following the exposure to the half-blue light display compared with the normal blue light display. These results suggest that the use of half-blue light displays during night time may prevent circadian rhythm dysfunction.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1446-9235 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number (up) LoNNe @ christopher.kyba @ Serial 1149
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