Bright light during wakefulness improves sleep quality in healthy men: A forced desynchrony study under dim and bright light (III)

R Lok*, T Woelders, M C M Gordijn, M J van Koningsveld, K Oberman, S G Fuhler, D G M Beersma, R A Hut

*Bijbehorende auteur voor dit werk

Onderzoeksoutput: ArticleAcademicpeer review

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Under real-life conditions, increased light exposure during wakefulness seems associated with improved sleep quality, quantified as reduced time awake during bed time, increased time spent in non-rapid eye movement (NREM) sleep, or increased power of the electroencephalogram delta band (0.5-4 Hz). The causality of these important relationships and their dependency on circadian phase and/or time awake has not been studied in depth. To disentangle possible circadian and homeostatic interactions, we employed a forced desynchrony protocol under dim light (6 lux) and under bright light (1300 lux) during wakefulness. Our protocol consisted of a fast cycling sleep-wake schedule (13 h wakefulness-5 h sleep; 4 cycles), followed by 3 h recovery sleep in a within-subject cross-over design. Individuals (8 men) were equipped with 10 polysomnography electrodes. Subjective sleep quality was measured immediately after wakening with a questionnaire. Results indicated that circadian variation in delta power was only detected under dim light. Circadian variation in time in rapid eye movement (REM) sleep and wakefulness were uninfluenced by light. Prior light exposure increased accumulation of delta power and time in NREM sleep, while it decreased wakefulness, especially during the circadian wake phase (biological day). Subjective sleep quality scores showed that participants rated their sleep quality better after bright light exposure while sleeping when the circadian system promoted wakefulness. These results suggest that high environmental light intensity either increases sleep pressure buildup during wakefulness or prevents the occurrence of micro-sleep, leading to improved quality of subsequent sleep.

Originele taal-2English
Pagina's (van-tot)429-441
Aantal pagina's13
TijdschriftJournal of Biological Rhythms
Nummer van het tijdschrift4
Vroegere onlinedatum22-jun.-2022
StatusPublished - aug.-2022

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