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Effects of evening bright light exposure on melatonin, body temperature and sleep
Author(s) -
BUNNELL DAVID E.,
TREIBER SCOTT P.,
PHILLIPS NATHAN H.,
BERGER RALPH J.
Publication year - 1992
Publication title -
journal of sleep research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 117
eISSN - 1365-2869
pISSN - 0962-1105
DOI - 10.1111/j.1365-2869.1992.tb00003.x
Subject(s) - melatonin , circadian rhythm , non rapid eye movement sleep , rectal temperature , sleep (system call) , evening , free running sleep , sleep stages , audiology , anesthesia , endocrinology , medicine , electroencephalography , polysomnography , physics , circadian clock , light effects on circadian rhythm , psychiatry , astronomy , computer science , operating system
SUMMARY Five male subjects were exposed to a single 2‐h period of bright (2500 lux) or dim (<100 lux) light prior to sleep on two consecutive nights. The two conditions were repeated the following week in opposite order. Bright light significantly suppressed salivary melatonin and raised rectal temperature 0.3°C (which remained elevated during the first 1.5 h of sleep), without affecting tympanic temperature. Bright light also increased REM latency, NREM period length, EEG spectral power in low frequency, 0.75‐8 Hz and sigma, 12–14 Hz (sleep spindle) bandwidths during the first hour of sleep, and power of all frequency bands (0.5–32 Hz) within the first NREMP. Potentiation of EEG slow wave activity (0.5‐4.0 Hz) by bright light persisted through the end of the second NREMP. The enhanced low‐frequency power and delayed REM sleep after bright light exposure could represent a circadian phase‐shift and/or the effect of an elevated rectal temperature, possibly mediated by the suppression of melatonin.