Proper Sleep May Help Clear Arteries

"We know that sleep deprivation does alter the physiology of numerous body systems, so it is not surprising that another health problem, or symptom or sign, should be related to sleep length," Parker said.

There is no precise formula for the length of sleep that is best for a given individual, Parker said. "There is considerable variation in sleep needs," she said. "On average, an individual needs between 7 and 8 hours of sleep. There is an increase in health problems with five hours or less or nine hours or more."

The best advice, said Parker, who is one of only five U.S. nurses certified by the American Board of Sleep Medicine, is "go to bed at a regular time, wake up at a regular time, pay attention to whether you feel refreshed and alert during the day, [and] avoid too much caffeine and alcohol."

As for sleeping pills, they are "appropriate in certain situations," such as times of acute psychological stress or jet lag or for "certain sleep disorders," Parker said.

"It's really important to wait until this finding is confirmed in another study population," Lauderdale cautioned. "Also, until we know the mechanism, it is premature to base clinical advice on this information."

More information

There's more on getting healthy sleep at the U.S. National Heart, Lung, and Blood Institute.

SOURCES: Diane Lauderdale, Ph.D., associate professor of health studies, Univesity of Chicago; Kathy P. Parker, Ph.D., R.N., dean, University of Rochester School of Nursing, N.Y.; Dec. 24/31, 2008, Journal of the American Medical Association