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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 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.
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ISSN 1446-9235 ISBN Medium
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Notes Approved no
Call Number LoNNe @ christopher.kyba @ Serial (down) 1149
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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.
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Publisher Wiley Place of Publication Editor
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Call Number IDA @ john @ Serial (down) 1098
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Author Paul, M.A.; Love, R.J.; Hawton, A.; Brett, K.; McCreary, D.R.; Arendt, J.
Title Sleep deficits in the high Arctic summer in relation to light exposure and behaviour: use of melatonin as a countermeasure Type Journal Article
Year 2015 Publication Sleep Medicine Abbreviated Journal Sleep Medicine
Volume Issue Pages
Keywords Human Health; Sleep
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ISSN 1389-9457 ISBN Medium
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Notes Approved no
Call Number LoNNe @ christopher.kyba @ Serial (down) 1093
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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 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
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ISSN 1389-9457 ISBN Medium
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Notes PMID:17420154 Approved no
Call Number LoNNe @ kagoburian @ Serial (down) 811
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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 School of Psychology, Flinders University, South Australia, Australia. leon.lack@flinders.edu.au
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ISSN 1087-0792 ISBN Medium
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Notes PMID:18603220 Approved no
Call Number LoNNe @ kagoburian @ Serial (down) 775
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