HANK MORGAN / SCIENCE PHOTO LIBRARY HANK MORGAN / SCIENCE PHOTO LIBRARY
Charles Czeisler. Portrait of Dr Charles Czeisler, researcher on human circadian rhythms. Circadian rhythms occur in humans as an internal biological clock which controls awake and sleep periods, daily change in body temperature, and metabolic activity. Czeisler has demonstrated that the human circadian rhythm is linked to exposure to bright light. By exposing night shift workers to bright light, Czeisler has been able to shift or delay this circadian rhythm. This research may assist night shift workers to stay more alert, and may be used to treat sleep disorders. Czeisler is director of the Boston Brigham and Women's Laboratory for Circadian Sleep Disorders, USA.
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