The Power of Circadian Rhythms
May 8, 2000 -- Circadian rhythms -- our 24-hour biological cycles -- govern more than our waking and sleeping. They affect when we are born, when we die, and how we pass the days in between.
Our body's rhythms are governed by a "master clock" located in a tiny region of the brain called the suprachiasmatic nucleus. It works much like a conductor, striking up one section of the body's orchestra as another quiets down, taking its main cue from light signals in order to stay in sync with the 24-hour day.
Our body's hormones surge and ebb to this maestro's invisible wand. Even our cells grow faster during certain hours of the day.
Here are just a few of the ways our circadian rhythms orchestrate our lives:
Findings such as these have led to the budding field of chronotherapy, in which doctors time medicines to the body's natural rhythms. For instance, allergy sufferers can ease their morning symptoms by taking a long-acting antihistamine late at night. Asthmatics can reduce their risk of a morning attack by taking the drug theophylline at night.
"We have found over 35 medical conditions that are affected by the body's internal clock," says Michael Smolensky, PhD, professor of environmental physiology at the University of Texas-Houston School of Public Health and co-author of The Body Clock Guide to Better Health. "That concept is revolutionary, and there's more coming."
Sarah Yang is a San Francisco reporter for WebMD.
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