Lack of deep sleep could contribute to weight gain in men

October 4, 2000
Web posted at: 3:08 PM EDT (1908 GMT)

From staff and wire reports

(CNN) -- As men age, they typically get less and less deep sleep -- a fact that could be connected to the weight gain that often accompanies middle-age, medical researchers said this week.

The link between sleep and love handles, double chins and expanding paunches centers on a hormone normally produced during deep sleep, the scientists from the University of Chicago reported in the August 16 issue of The Journal of the American Medical Association.

With less deep -- or slow-wave -- sleep, there is less bodily production of the growth hormone. That deficiency "is associated with increased fat tissue and abdominal obesity, reduced muscle mass and strength, and reduced exercise capacity," the article said. These results are particularly noted in the elderly.

"We actually know that if we increase deep sleep, we can increase growth hormone," said Eve Van Cauter, Ph.D., a University of Chicago professor of medicine who led the study.

That might enable scientists to slow the signs of aging through some kind of sleeping pill or hormone injection.

"The appearance of a paunch belly could be delayed by a decade or two," said Van Cauter.

She and her colleagues in the university’s department of medicine analyzed data from a series of studies conducted at four sleep laboratories between 1985 and 1999. The scientists studied the records of 149 healthy men aged 16 to 83. All were of normal weight, had no sleep complaints and no history of endocrine, psychiatric or sleep disorders.

The researchers found that by the time men reach age 45, they have nearly lost the ability to fall into deep sleep. The study also found that after age 50, men's total sleep declined by about 27 minutes per decade of age.

Since the study was limited to healthy men, it was not clear whether the findings apply to women. Other sleep studies have shown that pre-menopausal women get more deep sleep than men do, but after menopause, there is little difference.

Van Cauter said any treatment to improve a man's sleep would need to begin at age 35 to 40. The study found that deep sleep in men younger than 25 was about 20 percent of a night’s sleep. Between ages 25 and 35, the deep sleep drops to about 12 percent. After age 35, it’s 5 percent or less.

Growth hormone secretion declined by nearly 75 percent.

Deep sleep has several advantages besides increasing growth hormone.

"During deep sleep," Van Cauter said, "our blood pressure is lower and our heart rate is lower. So, in a way, deep sleep allows for a temporary relief of our cardiovascular system."

While Van Cauter is testing an experimental drug to see if it will increase deep sleep, some scientists wonder whether taking it would be worth the risk of medicating healthy people simply to delay natural aging.

Methods other than medicine can boost deep sleep -- for example, increasing body heat by taking a hot bath before bed. Exercising at least 20 minutes three or four times a week is also helpful.

The research was financially supported by the National Institute on Aging, by the National Institute of Diabetes and Digestive and Kidney Diseases and by the Mind-Body Network of the MacArthur Foundation, of Chicago.

CNN Medical Correspondent Elizabeth Cohen and The Associated Press contributed to this report.

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