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Charles Andrew Czeisler, MD, PhD
Senior Physician, Brigham and Women's Hospital
Frank Baldino, Jr., Ph.D. Professor of Sleep Medicine, Harvard Medical School

Brigham and Women's Hospital
Department of Medicine
Sleep and Circadian Disorders
75 Francis Street
Boston, MA 02115

Research Location: Boston Lying-In

Research Email:

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Research Narrative:
My laboratory research is focused on understanding the neurobiology of the human circadian pacemaker, located in the suprachiasmatic nucleus (SCN) of the hypothalamus, and its interaction with the sleep homeostat, and on applying that knowledge to clinical medicine and occupational health. We are examining the role of the pineal hormone melatonin in the organization of sleep and circadian rhythms. We are investigating the physiological mechanism underlying photic resetting of the human circadian pacemaker, having shown that some blind people without sight can retain normal circadian responsiveness to light. We are now investigating how the timing, duration, intensity and wavelength of light affects its circadian resetting capacity, which is mediated through intrinsically photosensitive retinal ganglion cells containing the novel photopigment melanopsin. Current research is aimed at functional determination of the photoreceptor(s) responsible for circadian vision in humans, on adaptation of circadian photoreceptors and on the after-effects of entrainment on circadian period in humans. We are investigating how circadian and homeostatic processes interact to regulate sleep and neurobiological function during wakefulness. Other ongoing research in the lab includes examining novel wakefulness- and sleep-promoting countermeasures, the effect of exercise on the circadian pacemaker, fMRI of the sleep deprived brain, the influence of aging on sleep and circadian rhythms, the influence of chronic sleep restriction on human performance, the influence of space flight on sleep and circadian rhythms and the application of our research to night workers-including medical residents and police-through the work of the Sleep Matters Initiative at Brigham Health.

Stanford Medical School, 1981, MD
Stanford University, 1978, PhD
Harvard College, 1974, AB

2019 Bernese Sleep Award University of Bern, Bern, Switzerland
2019 Peter C. Farrell Prize in Sleep Medicine, Harvard Medical School Division of Sleep Medicine
2019 J.E. Wallace Sterling Lifetime Achievement Award in Medicine, Stanford University School of Medicine Alumni Association
2018 Green Cross for Safety Innovation Award, National Safety Council
2014 Johnson Space Center Director's Innovation Award, NASA
2010 Elected as Member, International Academy of Astronautics
2010 Elected as Member, National Academy of Medicine

Courses Taught:
1982-present, Harvard College, Sleep and Circadian Clocks: from Biology to Public Health, The impact of the brain's circadian clock on sleep becomes evident when we travel across time zones or shift our sleep on weekends. How does this clock work? How does light from a tablet or smartphone affect our biology? What is the best time for sleep? What about naps? This course will explore the neurobiology of the brain's circadian clock that regulates the timing and structure of sleep, its interaction with the periodic environment, and the consequences of circadian disruption in our 24/7 society on health, performance and safety.

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