|   | 
Details
   web
Records
Author Santhi, N.; Thorne, H.C.; van der Veen, D.R.; Johnsen, S.; Mills, S.L.; Hommes, V.; Schlangen, L.J.M.; Archer, S.N.; Dijk, D.-J.
Title The spectral composition of evening light and individual differences in the suppression of melatonin and delay of sleep in humans Type Journal Article
Year 2012 Publication Journal of Pineal Research Abbreviated Journal (up) J Pineal Res
Volume 53 Issue 1 Pages 47-59
Keywords Human Health; Adult; *Circadian Clocks; Cross-Sectional Studies; Electroencephalography; Female; Humans; Male; Melatonin/*metabolism; Photic Stimulation; *Photoperiod; Rod Opsins/*metabolism; *Sleep; *Sleep Disorders, Circadian Rhythm/etiology/metabolism/physiopathology; Time Factors
Abstract The effect of light on circadian rhythms and sleep is mediated by a multi-component photoreceptive system of rods, cones and melanopsin-expressing intrinsically photosensitive retinal ganglion cells. The intensity and spectral sensitivity characteristics of this system are to be fully determined. Whether the intensity and spectral composition of light exposure at home in the evening is such that it delays circadian rhythms and sleep also remains to be established. We monitored light exposure at home during 6-8wk and assessed light effects on sleep and circadian rhythms in the laboratory. Twenty-two women and men (23.1+/-4.7yr) participated in a six-way, cross-over design using polychromatic light conditions relevant to the light exposure at home, but with reduced, intermediate or enhanced efficacy with respect to the photopic and melanopsin systems. The evening rise of melatonin, sleepiness and EEG-assessed sleep onset varied significantly (P<0.01) across the light conditions, and these effects appeared to be largely mediated by the melanopsin, rather than the photopic system. Moreover, there were individual differences in the sensitivity to the disruptive effect of light on melatonin, which were robust against experimental manipulations (intra-class correlation=0.44). The data show that light at home in the evening affects circadian physiology and imply that the spectral composition of artificial light can be modified to minimize this disruptive effect on sleep and circadian rhythms. These findings have implications for our understanding of the contribution of artificial light exposure to sleep and circadian rhythm disorders such as delayed sleep phase disorder.
Address Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK. n.santhi@surrey.ac.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 0742-3098 ISBN Medium
Area Expedition Conference
Notes PMID:22017511 Approved no
Call Number LoNNe @ kagoburian @ Serial 802
Permanent link to this record
 

 
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 (up) 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 IDA @ john @ Serial 348
Permanent link to this record
 

 
Author Bennett, S.; Alpert, M.; Kubulins, V.; Hansler, R.L.
Title Use of modified spectacles and light bulbs to block blue light at night may prevent postpartum depression Type Journal Article
Year 2009 Publication Medical Hypotheses Abbreviated Journal (up) Med Hypotheses
Volume 73 Issue 2 Pages 251-253
Keywords Depression, Postpartum/*prevention & control; *Eyeglasses; Female; Humans; *Lighting; blue light; light therapy; blue blocker
Abstract In 2001 it was discovered that exposing the eyes to light in the blue end of the visible spectrum suppresses the production of the sleep hormone, melatonin. New mothers need to get up during the night to care for their babies. This is the time when melatonin is normally flowing. Exposing their eyes to light can cut off the flow. It may also reset their circadian (internal) clock. On subsequent nights the melatonin may not begin flowing at the normal time making it difficult to fall asleep. Over time, disruption of the circadian rhythm plus sleep deprivation may result in depression. Women suffering postpartum depression were enrolled in a small clinical trial. Some were provided with glasses and light bulbs that block blue light. Others were equipped with glasses and light bulbs that looked colored but did not block the rays causing melatonin suppression. Those with the “real glasses” recovered somewhat more quickly than those with the placebo glasses and light bulbs. The hypothesis that should be tested in large scale clinical trials is that the risk of postpartum depression can be reduced when a new mother avoids exposing her eyes to blue light when she gets up at night to care for her baby. In the meantime, all new mothers may benefit from using glasses and light bulbs that block blue light when getting up at night to care for their babies.
Address Postpartum Support, International P.O. Box 60931, Santa Barbara, CA 93160, 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 0306-9877 ISBN Medium
Area Expedition Conference
Notes PMID:19329259 Approved no
Call Number IDA @ john @ Serial 296
Permanent link to this record
 

 
Author Czeisler, C.A.; Shanahan, T.L.; Klerman, E.B.; Martens, H.; Brotman, D.J.; Emens, J.S.; Klein, T.; Rizzo, J.F. 3rd
Title Suppression of melatonin secretion in some blind patients by exposure to bright light Type Journal Article
Year 1995 Publication The New England Journal of Medicine Abbreviated Journal (up) N Engl J Med
Volume 332 Issue 1 Pages 6-11
Keywords Human Health; Adolescent; Adult; Aged; Blindness/etiology/*physiopathology; Circadian Rhythm; Female; Humans; *Light; Male; Melatonin/blood/*secretion; Middle Aged; Photic Stimulation; Sleep Initiation and Maintenance Disorders/physiopathology; Visual Perception
Abstract BACKGROUND: Complete blindness generally results in the loss of synchronization of circadian rhythms to the 24-hour day and in recurrent insomnia. However, some blind patients maintain circadian entrainment. We undertook this study to determine whether some blind patients' eyes convey sufficient photic information to entrain the hypothalamic circadian pacemaker and suppress melatonin secretion, despite an apparently complete loss of visual function. METHODS: We evaluated the input of light to the circadian pacemaker by testing the ability of bright light to decrease plasma melatonin concentrations in 11 blind patients with no conscious perception of light and in 6 normal subjects. We also evaluated circadian entrainment over time in the blind patients. RESULTS: Plasma melatonin concentrations decreased during exposure to bright light in three sightless patients by an average (+/- SD) of 69 +/- 21 percent and in the normal subjects by an average of 66 +/- 15 percent. When two of these blind patients were tested with their eyes covered during exposure to light, plasma melatonin did not decrease. The three blind patients reported no difficulty sleeping and maintained apparent circadian entrainment to the 24-hour day. Plasma melatonin concentrations did not decrease during exposure to bright light in seven of the remaining blind patients; in the eighth, plasma melatonin was undetectable. These eight patients reported a history of insomnia, and in four the circadian temperature rhythm was not entrained to the 24-hour day. CONCLUSIONS: The visual subsystem that mediates light-induced suppression of melatonin secretion remains functionally intact in some sightless patients. The absence of photic input to the circadian system thus constitutes a distinct form of blindness, associated with periodic insomnia, that afflicts most but not all patients with no conscious perception of light.
Address Department of Medicine, Harvard Medical School, Boston, MA 02115
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 0028-4793 ISBN Medium
Area Expedition Conference
Notes PMID:7990870 Approved no
Call Number LoNNe @ kagoburian @ Serial 732
Permanent link to this record
 

 
Author Nadis, S.
Title Biologists join drive to turn down the lights Type
Year 2002 Publication Nature Abbreviated Journal (up) Nature
Volume 419 Issue 6910 Pages 868
Keywords Ecology; Animal Migration; Animals; Astronomical Phenomena; Astronomy; Biology/*trends; Breast Neoplasms/etiology; Environment; Environmental Pollution/*adverse effects/prevention & control; Female; Humans; Light/*adverse effects; Male; Risk Factors; Vision, Ocular/physiology
Abstract
Address
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 0028-0836 ISBN Medium
Area Expedition Conference
Notes PMID:12410271 Approved no
Call Number LoNNe @ kagoburian @ Serial 787
Permanent link to this record