STANFORD, Calif. - The less you sleep, the more you may gain. So say Stanford University School of Medicine researchers, who found in a recent study that sleep loss leads to higher levels of a hormone that triggers appetite, lower levels of a hormone that tells your body it's full and an increased body mass index.

The findings not only add to the growing body of evidence showing that sleep duration may be an important regulator of body weight and metabolism, but they also document for the first time the relationship between sleep and these hormones in the general population, tracking how hormonal changes are consistent with obesity.

The paper by Emmanuel Mignot, MD, PhD, associate professor of psychiatry and behavioral sciences, and colleagues at Stanford and the University of Wisconsin is published in the Dec. 6 online issue of Public Library of Science.

"Our results demonstrate an important relationship between sleep and metabolic hormones," the researchers noted in the paper. "In Western societies, where chronic sleep restriction is common and food is widely available, changes in appetite regulatory hormones with sleep curtailment may contribute to obesity."

Past studies have indicated an association between sleep loss and increased body mass index, or BMI. A study presented last month at a meeting of the North American Association for the Study of Obesity, for example, found that people who sleep two to four hours a night were 73 percent more likely to be obese than normal sleepers.

Researchers believe that sleep loss impacts several hormones related to appetite and food intake, and two such hormones - ghrelin and leptin - are thought to play a role in the interaction between short sleep duration and high BMI.

Ghrelin, which was discovered five years ago and is primarily produced by the stomach, triggers app
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Contact: Michelle Brandt
mbrandt@stanford.edu
Stanford University Medical Center
6-Dec-2004