School Start Time Conference - Session 01:

An Overview of the Biology of Sleep and Circadian Rhythms - Daniel J. Buysse, MD


Daniel J. Buysse, MD, UPMC Endowed Chair in Sleep Medicine and Professor of Psychiatry and Clinical and Translational Science, University of Pittsburgh

Dr. Buysse presents an overview of the biology of circadian rhythms and sleep. He starts by noting that sleep is a key pillar of health and that poor sleep has been associated with a variety of adverse health outcomes, including diabetes, coronary heart disease, obesity, hypertension, and early mortality. 

Dr. Buysse explains that circadian rhythms are 24-hour biological processes that evolved in the brain to adapt to life on a rotating planet. He describes in layman's terms how the brain’s superchiasmatic nucleus serves as the body’s “master clock.” Operating through various genes in the brain, the superchiasmatic nucleus takes cues from our external environment to synchronize the genes and circadian clocks that reside in and regulate the cyclical activity in every cell in the body.

Dr. Buysse next describes the various systems the brain uses to promote daily cycles of wakefulness and of sleep, and the processes that control these systems.  Having outlined the biology of circadian rhythm and sleep, Dr. Buysse discusses the various dimensions of sleep that contribute to good health, including sleep regularity, duration, timing, and continuity. 

Dr. Buysse concludes by outlining a causal feedback loop in which the body’s circadian timing system is designed to drive sleep patterns and behaviors, which operate through changes in physiology to promote physical, mental, and cognitive health. 

On a final note, Dr. Buysse suggests that, with an understanding of the critical relationships linking circadian rhythms, sleep, and adolescent health, it becomes the responsibility of school leaders to design policies that leverage that understanding.

Daniel J. Buysse, MD
Daniel Buysse is the UPMC Professor of Sleep Medicine and Professor of Psychiatry and Clinical and Translational Science at the University of Pittsburgh. His research focuses on sleep assessment; the pathophysiology and treatment of insomnia; interactions between sleep and circadian rhythms; and the impact of sleep on health. Dr. Buysse has received research funding from the National Institute of Mental Health, the National Institute on Aging, and the National Heart, Lung, and Blood Institute. He has published over 300 peer-reviewed articles and over 100 book chapters or review articles. Dr. Buysse is Past President of the American Academy of Sleep Medicine; recipient of the Nathaniel Kleitman Distinguished Service Award from the American Academy of Sleep Medicine and the Mary A. Carskadon Outstanding Educator Award from the Sleep Research Society; and Deputy Editor of SLEEP.