Charles Czeisler

About

Dr. Charles Czeisler is a Professor of Sleep Medicine at Brigham and Women's Hospital, affiliated with the Division of Sleep Medicine. He has over 40 years of experience in basic and applied research focusing on the physiology of the human circadian timing system and its relationship to the sleep-wake cycle. His research interests include the physiology of the hypothalamic circadian pacemaker in humans, photic and non-photic synchronizers of the human circadian pacemaker, and the temporal dynamics in neuroendocrine systems. Dr. Czeisler investigates homeostatic and circadian factors in the regulation of sleep and alertness, as well as the impact of sleep and circadian disturbances and disorders on health, safety, and development. He applies sleep and circadian physiology to occupational medicine and health policy, particularly concerning extended work shifts and long work weeks.

Research topics

• Medicine
• Medical emergency
• Virology
• Internal medicine
• Computer Science
• Ecology
• Nursing
• Pathology
• Cognitive psychology
• Environmental health

Selected publications

• Delay or Avoidance of Medical Care Because of COVID-19–Related Concerns — United States, June 2020

  MMWR Morbidity and Mortality Weekly Report · 2020 · 1546 citations

  versus those without disabilities (aPR = 1.3). Given this widespread reporting of medical care avoidance because of COVID-19 concerns, especially among persons at increased risk for severe COVID-19, urgent efforts are warranted to ensure delivery of services that, if deferred, could result in patient harm. Even during the COVID-19 pandemic, persons experiencing a medical emergency should seek and be provided care without delay (3).

  DOI

• Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults

  PLoS Biology · 2022 · 540 citations

  Ocular light exposure has important influences on human health and well-being through modulation of circadian rhythms and sleep, as well as neuroendocrine and cognitive functions. Prevailing patterns of light exposure do not optimally engage these actions for many individuals, but advances in our understanding of the underpinning mechanisms and emerging lighting technologies now present opportunities to adjust lighting to promote optimal physical and mental health and performance. A newly develo…

  DOI

• Effect on Patient Safety of a Resident Physician Schedule without 24-Hour Shifts

  New England Journal of Medicine · 2020 · 95 citations

  Senior authorCorresponding

  BACKGROUND: The effects on patient safety of eliminating extended-duration work shifts for resident physicians remain controversial. METHODS: We conducted a multicenter, cluster-randomized, crossover trial comparing two schedules for pediatric resident physicians during their intensive care unit (ICU) rotations: extended-duration work schedules that included shifts of 24 hours or more (control schedules) and schedules that eliminated extended shifts and cycled resident physicians through day and…

  DOI

• Resident Physician Intentions Regarding Unionization

  JAMA Network Open · 2025-04-03 · 6 citations

  articleOpen accessSenior author

  Importance: Resident physicians provide frontline care to approximately 70% of hospitalized patients. After decades of relative stability with a small minority of resident physicians unionized, unionization movements have succeeded in recent years at multiple major academic medical centers. Objective: To evaluate resident physicians' unionization intention and the factors informing their unionization consideration at their institution. Design, Setting, and Participants: This nationwide survey st…

  PublisherOA PDFDOI

• Obstructive sleep apnea is a risk factor for incident COVID-19 infection

  Sleep And Breathing · 2025-06-25 · 3 citations

  articleSenior author
  PublisherDOI

Recent grants

• NIH Grant P30HL101299

  NIH · $733k · 2012

• NIH Grant R01OH009403

  NIH · $467k · 2010

• NIH Grant R01GM105018

  NIH · $1.9M · 2018

Frequent coauthors

• Laura K. Barger

  Harvard University

  826 shared

• Shantha M. W. Rajaratnam

  Austin Health

  822 shared

• Steven W. Lockley

  717 shared

• Jeanne F. Duffy

  Harvard University

  529 shared

• Matthew D. Weaver

  507 shared

• Elizabeth B. Klerman

  University of Oxford

  468 shared

• Mark É. Czeisler

  Harvard University

  423 shared

• Stuart F. Quan

  374 shared

Labs

• Charles Czeisler LabPI

Education

• Ph.D., Neuroscience

  Harvard University

  1981

• M.D.

  Harvard Medical School

  1977

• B.A., Psychology

  University of Pennsylvania

  1973

Similar researchers at Harvard University

• Constance L. Cepkoh-149
• Xandra Breakefieldh-141
• Junying Yuanh-133