More shuteye, slimmer bods?

More shuteye, slimmer bods?
By CHRISTINE DELL'AMORE
WASHINGTON, May 23 (UPI) -- Women who doze seven hours a night aren't only getting their beauty sleep. New research shows sleeping more can prevent weight gain in women over time, whereas slumbering five hours or less packs on the pounds.

In the study, the incidence of major weight gain -- 33 pounds or more -- rose 32 percent for women who slept five hours a night. These women were also 15 percent more likely to become obese.

The research is the largest study to date to follow the effects of sleep on weight over an extended period of time, rather than a cross-sectional, or one-time, observation.

"This adds to growing evidence that it's important to allow yourself to get more sleep," said Dr. Sanjay Patel, professor of medicine at Case Western Reserve University in Cleveland.

Patel presented his research Tuesday at the American Thoracic Society International Conference in San Diego.

Patel and colleagues followed more than 68,000 middle-aged women in the Nurses' Health Study, a large, long-term federal study of registered nurses. The women, who were free of major diseases, were asked in 1986 to describe how many hours a night they typically slept. The women then reported their weight to researchers every two years until 2002.

At the start of the study, the women who slept five hours or less already weighed 5.4 pounds more than those who slept longer. Although all the women gained weight over the 16 years, the women who slept five hours or less gained more, an average of 1.5 pounds, when the data were adjusted for various factors including caffeine intake, medication or alcohol use. Although this is a relatively small increase in weight, Patel said, the women's risk of developing obesity went up considerably.

Previous research suggests restricting sleep has crucial metabolic effects that can lead to weight gain. For instance, if people are sleep-deprived, their altered hormones may cause increased hunger. They may also feel more fatigued, and thus exercise less. Even so, it's unclear whether being overweight shortens sleep, or sleeping less predisposes a person to gain weight.

However, Patel and colleagues' work may indicate less sleep can predict how much weight a person gains in the future, at least in women.

(Other studies have observed the same connections between sleep deprivation and weight gain in men.)

Some of the data also puzzled researchers: Women who slept less took in fewer calories than women who slept more. So, how many calories the women ate did not dictate how much they weighed. Similarly, the women's exercise patterns did not explain why the women who slept less weighed more.

This also surprised Dr. Emmanuel Mignot, Stanford's Howard Hughes Medical Institute investigator on sleep research. It could be the data was imperfectly measured, as it's hard to pinpoint exactly what people eat and exactly how much calories they expend, he said.

Regardless, Mignot told UPI intervention studies are needed to move this sleep-obesity connection beyond a passive causality.

"This study is tantalizing, but it's not yet proof," Mignot said.

The NIH already has an intervention study in the works for summer 2006, which will recruit obese men and women between the ages of 22-50 who usually sleep less than six hours a night. Researchers want to see the impact of sleeping a normal number of hours in obese subjects who habitually sleep six hours, said Dr. Giovanni Cizza, a clinician at the NIH's National Institute of Diabetes & Digestive & Kidney Diseases.

The backdrop of all this research is an overall decline in the quality and length of slumber for Americans. The time Americans spend snoozing has been falling over the past 25 years.

For example, in 2005, 40 percent of Americans reported getting less than seven hours of sleep a night, according to a survey by the National Sleep Foundation. Many doctors suggest eight to nine hours of sleep is ideal for adults to function fully.

In general, the survey also found women need more sleep than men: One-third of female respondents report requiring eight or more hours of sleep.

A sleep-deprived nation could have an enormous public health impact, experts say.

[link to www.upi.com]

Last Edited by Phennommennonn on 10/24/2011 12:06 PM