Women who sleep less than five hours a night are 32 times more likely to gain more than 30 pounds, Ohio researchers told a San Diego conference.
Such women also are 15 percent more likely to become obese vs. women who sleep more than five hours a night, concludes a Case Western Reserve University study.
The study examined data of 70,000 middle-aged participants in the Nurses Health Study.
"Sleeping less may effect changes in a person's basal metabolic rate -- the number of calories you burn when you rest," said researcher Sanjay Patel.
Another contributor may be involuntary fidgeting, he said.
"It may be that if you sleep less, you move around less, too, and therefore burn up fewer calories," Patel said.
While other studies have shown that people who sleep less weigh more, Patel said his is the first to show reduced sleep increases the weight-gain risk, the Web site Earthtimes.org reported.
The findings were presented at the American Thoracic Society's international conference in San Diego.
Copyright 2006 by United Press International
Explore further: Study examines top high school students' stress and coping mechanisms