Cited by 770Circadian rhythm and melatoninSleep and Work-Related FatigueImpact of Light on Environment and Health

Bright light resets the human circadian pacemaker independent of the timing of the sleep-wake cycle

Czeisler, Charles A., Allan, James S., Strogatz, Steven H., Ronda, Joseph M., Sánchez, Ramiro, Ríos, C. David, Freitag, Walter O., Richardson, Gary S. +1 more·1986·Science

Abstract

Human circadian rhythms were once thought to be insensitive to light, with synchronization to the 24-hour day accomplished either through social contacts or the sleep-wake schedule. Yet the demonstration of an intensity-dependent neuroendocrine response to bright light has led to renewed consideration of light as a possible synchronizer of the human circadian pacemaker. In a laboratory study, the output of the circadian pacemaker of an elderly woman was monitored before and after exposure to 4 hours of bright light for seven consecutive evenings, and before and after a control study in ordinary room light while her sleep-wake schedule and social contacts remained unchanged. The exposure to bright light in the evening induced a 6-hour delay shift of her circadian pacemaker, as indicated by recordings of body temperature and cortisol secretion. The unexpected magnitude, rapidity, and stability of the shift challenge existing concepts regarding circadian phase-resetting capacity in man and suggest that exposure to bright light can indeed reset the human circadian pacemaker, which controls daily variations in physiologic, behavioral, and cognitive function.

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Registry

Crossref · 10.1126/science.3726555

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29 of 29 references verified0 citation errors · 0 not checkable

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  • Light is the most important and potent synchronizer for the human circadian system.

    “Light is the most important and potent synchronizer for the human circadian system (Czeisler et al., 1986, Klerman and Rimmer, 1998).”

    From Circadian dysregulation in Parkinson's disease (2017) · cites this paper as Czeisler et al., 1986

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Authors
Czeisler, C. A., Allan, J. S., Strogatz, S. H., Ronda, J. M., Sánchez, R., Ríos, C. D., Freitag, W. O., Richardson, G. S., & Kronauer, R. E.
Affiliations
  • Brigham and Women's Hospital (US)
  • Harvard University (US)
  • Neuroendocrinology Laboratory, Division of Endocrinology, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115.
Venue
Science
Published
1986-08-08
Volume
233
Issue
4764
Pages
667-671
ISSN
  • 0036-8075 (ISSN-L)
  • 1095-9203
OpenAlex
W2003623977
Cited by
770
References
28
Citations by year
2026: 12 · 2025: 17 · 2024: 15 · 2023: 24 · 2022: 25 · 2021: 14 · 2020: 25 · 2019: 23 · 2018: 19 · 2017: 23 · 2016: 27 · 2015: 17 · 2014: 27 · 2013: 19 · 2012: 27
FWCI
12.02
Type
journal article
Language
en
Open access
closed
Locations
  • Science (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • National Institutes of Health (5r01hd020174-03)
  • U.S. Public Health Service (AFOSR-83-0309)
  • National Institute on Aging (1 R01-AG-04912-02)
  • Eunice Kennedy Shriver National Institute of Child Health and Human Development (1 R01-HD-20174-01)
Topics
  • Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Circadian rhythm and melatonin
  • Social Sciences › Psychology › Experimental and Cognitive Psychology › Sleep and Work-Related Fatigue
  • Physical Sciences › Environmental Science › Global and Planetary Change › Impact of Light on Environment and Health
Keywords
circadian pacemaker, phase resetting, bright light exposure, circadian synchronization, circadian phase shift, body temperature, cortisol secretion, sleep-wake cycle, older women
MeSH terms
Aged, Body Temperature, Circadian Rhythm, Female, Humans, Hydrocortisone, Light, Sleep

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