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Author Lack, L.C.; Gradisar, M.; Van Someren, E.J.W.; Wright, H.R.; Lushington, K.
Title The relationship between insomnia and body temperatures Type Journal Article
Year 2008 Publication Sleep Medicine Reviews Abbreviated Journal Sleep Med Rev
Volume 12 Issue 4 Pages 307-317
Keywords Human Health; Arousal/physiology; Body Temperature Regulation/*physiology; Circadian Rhythm/physiology; Homeostasis/physiology; Humans; Melatonin/blood; Phototherapy; Skin Temperature/physiology; Sleep Disorders, Circadian Rhythm/physiopathology/therapy; Sleep Initiation and Maintenance Disorders/*physiopathology/therapy; Sympathetic Nervous System/physiopathology; Wakefulness/physiology
Abstract Sleepiness and sleep propensity are strongly influenced by our circadian clock as indicated by many circadian rhythms, most commonly by that of core body temperature. Sleep is most conducive in the temperature minimum phase, but is inhibited in a “wake maintenance zone” before the minimum phase, and is disrupted in a zone following that phase. Different types of insomnia symptoms have been associated with abnormalities of the body temperature rhythm. Sleep onset insomnia is associated with a delayed temperature rhythm presumably, at least partly, because sleep is attempted during a delayed evening wake maintenance zone. Morning bright light has been used to phase advance circadian rhythms and successfully treat sleep onset insomnia. Conversely, early morning awakening insomnia has been associated with a phase advanced temperature rhythm and has been successfully treated with the phase delaying effects of evening bright light. Sleep maintenance insomnia has been associated not with a circadian rhythm timing abnormality, but with nocturnally elevated core body temperature. Combination of sleep onset and maintenance insomnia has been associated with a 24-h elevation of core body temperature supporting the chronic hyper-arousal model of insomnia. The possibility that these last two types of insomnia may be related to impaired thermoregulation, particularly a reduced ability to dissipate body heat from distal skin areas, has not been consistently supported in laboratory studies. Further studies of thermoregulation are needed in the typical home environment in which the insomnia is most evident.
Address (up) School of Psychology, Flinders University, South Australia, Australia. leon.lack@flinders.edu.au
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 1087-0792 ISBN Medium
Area Expedition Conference
Notes PMID:18603220 Approved no
Call Number LoNNe @ kagoburian @ Serial 775
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Author Akacem, L.D.; Wright, K.P.J.; LeBourgeois, M.K.
Title Bedtime and evening light exposure influence circadian timing in preschool-age children: A field study Type Journal Article
Year 2016 Publication Neurobiology of Sleep and Circadian Rhythms Abbreviated Journal Neurobiol Sleep Circadian Rhythms
Volume 1 Issue 2 Pages 27-31
Keywords Human Health
Abstract Light exposure and sleep timing are two factors that influence inter-individual variability in the timing of the human circadian clock. The aim of this study was to quantify the degree to which evening light exposure predicts variance in circadian timing over and above bedtime alone in preschool children. Participants were 21 children ages 4.5-5.0 years (4.7 +/- 0.2 years; 9 females). Children followed their typical sleep schedules for 4 days during which time they wore a wrist actigraph to assess sleep timing and a pendant light meter to measure minute-by-minute illuminance levels in lux. On the 5th day, children participated in an in-home dim-light melatonin onset (DLMO) assessment. Light exposure in the 2 h before bedtime was averaged and aggregated across the 4 nights preceding the DLMO assessment. Mean DLMO and bedtime were 19:22 +/- 01:04 and 20:07 +/- 00:46, respectively. Average evening light exposure was 710.1 +/- 1418.2 lux. Children with later bedtimes (lights-off time) had more delayed melatonin onset times (r=0.61, p=0.002). Evening light exposure was not independently associated with DLMO (r=0.32, p=0.08); however, a partial correlation between evening light exposure and DLMO when controlling for bedtime yielded a positive correlation (r=0.46, p=0.02). Bedtime explained 37.3% of the variance in the timing of DLMO, and evening light exposure accounted for an additional 13.3% of the variance. These findings represent an important step in understanding factors that influence circadian phase in preschool-age children and have implications for understanding a modifiable pathway that may underlie late sleep timing and the development of evening settling problems in early childhood.
Address (up) Sleep and Development Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, 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 2451-9944 ISBN Medium
Area Expedition Conference
Notes PMID:28042611; PMCID:PMC5193478 Approved no
Call Number LoNNe @ kyba @ Serial 1755
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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 (up) 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 IDA @ john @ Serial 349
Permanent link to this record