Charles Andrew Czeisler (born November 1952) is a Hungarian-American physician and sleep and circadian researcher. He is a leading researcher and author in the fields of the effects of light on human physiology, circadian rhythms and sleep medicine.
Background and education
Czeisler graduated from Harvard College, magna cum laude in 1974, with a degree in biochemistry and molecular biology. His undergraduate thesis was focused on cortisol timing release. He then studied at Stanford University, where he received his Ph.D. in neuro- and bio-behavioral sciences in 1978 and his M.D. in 1981. As a graduate student at Stanford, Czeisler continued his research in Dr. William Dement's lab. Dr. Elliot Weitzman, who both worked with and mentored Czeisler, influenced Czeisler to study sleep. Today, Czeisler is the Baldino Professor of Sleep Medicine and Director of the Division of Sleep Medicine at Harvard Medical School. Additionally, he works as the Division Chief of Sleep Medicine at Brigham and Women's Hospital in Boston, Massachusetts.
Czeisler has spent over 40 years researching the relationship between light and human physiology, particularly, the physiology of the human circadian clock. He teaches a course at Harvard College on Circadian Biology for undergraduate and graduate students. He was ultimately inducted into the Phi Beta Kappa Society (ΦΒΚ) at Harvard College in 1999. In addition to his work at Harvard Medical School and Brigham and Women's Hospital, Czeisler is a Diplomate of the American Board of Sleep Medicine, an elected member of the National Academy of Medicine, the International Academy of Astronautics and the American Clinical and Climatological Association, and a Fellow of the Royal College of Physicians, American Society for Clinical Investigation, and Association of American Physicians.
Family life
Czeisler was one of Tibor Czeisler and Wanda Victoria Murzyn's three children. In 1993, Czeisler married Theresa Lynn Shanahan M.D. They now have three children and live in the Boston area. In his free time, Czeisler enjoys swimming, playing pickleball, and slalom waterskiing.
Research interests
Czeisler's research focus is the neurobiology of human circadian rhythm, the functions and physiology of sleep, the epidemiology and public health consequences of sleep disorders, and the applications of circadian and sleep principles in clinical medicine and occupational safety and health. He also examines the relationship between the circadian oscillator and sleep homeostasis, including a landmark 1980 Science paper demonstrating that sleep episodes were correlated with the circadian phase of the body temperature rhythm at bedtime and not with the length of prior wakefulness. Czeisler's research interests encompass many areas, including the effects of light on human circadian rhythms, the role of sleep and circadian rhythms in metabolism, the impact of shift work on health and productivity, and the effects of melatonin and melatonin receptor agonists on humans.
Czeisler investigates how the physiological system works to reset the human central circadian pacemaker, located in the hypothalamus and called the suprachiasmatic nucleus (SCN). Among his most salient contributions to this research area are a pair of seminal Science original research articles published in 1986 and 1989. The first, entitled "Bright light resets the human circadian pacemaker independent of the timing of the sleep-wake cycle," provided convincing evidence that light influences the human circadian pacemaker, contributing to control of daily variations in physiologic, behavioral, and cognitive function. This finding challenged the then-common idea that synchronization to the 24-hour day accomplished either through social contacts or the sleep-wake schedule. This scientific breakthrough was featured on the front page of The New York Times in June 1989.