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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 (up) 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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Language English Summary Language Original Title
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ISSN 1389-9457 ISBN Medium
Area Expedition Conference
Notes PMID:21704557; PMCID:PMC3145013 Approved no
Call Number IDA @ john @ Serial 303
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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 (up) 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
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Series Volume Series Issue Edition
ISSN 1389-9457 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 349
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Author Kim, J.; Hwang, K.; Cho, J.; Koo, D.; Joo, E.; Hong, S.
Title Effect of bedside light on sleep quality and background eeg rhythms Type Journal Article
Year 2013 Publication (up) Sleep Medicine Abbreviated Journal Sleep Medicine
Volume 14 Issue Pages e170
Keywords Human Health
Abstract Artificial lighting has benefited society by extending the length of a productive day, but it can be ”light pollution” when it becomes excessive. Unnecessary exposure to artificial light at night can cause myopia, obesity, metabolic disorders and even some type of cancers.
Address
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Language Summary Language Original Title
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ISSN 1389-9457 ISBN Medium
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Notes Approved no
Call Number LoNNe @ christopher.kyba @ Serial 502
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Author Dumont, M.; Beaulieu, C.
Title Light exposure in the natural environment: relevance to mood and sleep disorders Type Journal Article
Year 2007 Publication (up) Sleep Medicine Abbreviated Journal Sleep Med
Volume 8 Issue 6 Pages 557-565
Keywords Human Health; Affect; *Biological Clocks; *Circadian Rhythm; Humans; *Light; Mood Disorders/*etiology; Sleep Disorders, Circadian Rhythm/*complications; Wakefulness; Work Schedule Tolerance
Abstract In addition to being necessary for vision, light also plays a primary role in circadian physiology. Humans are diurnal animals and their biological clock synchronizes their physiological functions in such a way that functions associated with activity happen in the daytime while functions associated with rest occur at night. A misalignment between the endogenous circadian clock and the desired sleep schedule is the main cause of circadian sleep disorders; it may be involved in certain mood disorders as well. Since light is the main environmental cue used by the biological clock to set its own timing in relation to the day-night cycle, inappropriate light exposure can be involved in the physiopathology of circadian disorders. Conversely, when handled properly, controlled light exposure can be used to treat some mood and sleep disorders. While the earliest studies in the field focused solely on exposure to bright light, contemporary studies aim at understanding how the entire profile of light-dark exposure can influence the circadian clock and, consequently, mood, sleep, and vigilance quality. Following a brief summary of the main concepts underlying the non-visual effects of light, this paper presents some studies using ambulatory measurements of light exposure to illustrate how these concepts apply in real-life situations and discusses the clinical relevance of light exposure in the natural environment for mood, sleep, and circadian disorders.
Address Chronobiology Laboratory, Sacre-Coeur Hospital of Montreal, Montreal, Quebec, Canada H4J 1C5. marie.dumont@umontreal.ca
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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:17383230 Approved no
Call Number LoNNe @ kagoburian @ Serial 736
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Author Skene, D.J.; Arendt, J.
Title Circadian rhythm sleep disorders in the blind and their treatment with melatonin Type Journal Article
Year 2007 Publication (up) Sleep Medicine Abbreviated Journal Sleep Med
Volume 8 Issue 6 Pages 651-655
Keywords Human Health; Blindness/*complications; Chronotherapy; Circadian Rhythm/drug effects; Humans; Melatonin/*administration & dosage; Sleep/drug effects; Sleep Disorders, Circadian Rhythm/*drug therapy/*etiology; Treatment Outcome
Abstract People who are blind, in addition to having to cope with partial or no sight, have an added handicap; the transmission of ocular light from the retina to their circadian clock is impaired. At its worse, for example in people with both eyes enucleated, this lesion results in desynchronisation of the biological clock (located in the hypothalamic suprachiasmatic nuclei) from the 24h day/night environment. While in a desynchronised state, symptoms akin to jet lag are experienced (e.g., daytime sleepiness, poor night sleep, reduced alertness and performance during waking). This is a lifelong condition. Daily administration of exogenous melatonin is the current treatment of choice for this so-called “non-24h sleep/wake disorder”. Melatonin has been shown to correct the underlying circadian rhythm abnormality as well as improve sleep and reduce daytime napping. The effectiveness of melatonin therapy depends upon its time of administration relative to the timing of the person's circadian clock. If practicable, assessment of an individual's circadian phase (by measurement of the endogenous melatonin rhythm in plasma, saliva or urine) is recommended prior to commencing treatment to optimise melatonin's effectiveness.
Address Centre for Chronobiology, School of Biomedical and Molecular Sciences, University of Surrey, Guildford GU2 7XH, UK. d.skene@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 1389-9457 ISBN Medium
Area Expedition Conference
Notes PMID:17420154 Approved no
Call Number LoNNe @ kagoburian @ Serial 811
Permanent link to this record