Investigations

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As men move into middle age, they spend less time in deep sleep. This decline may be linked to the decrease in the body's production of the human growth hormone (HGH) and may contribute to the aging process, including wear-and-tear of the cardiovascular system and the tendency toward middle-age spread: love handles, double chins, and potbellies.

A study led by Chicago professor of medicine Eve Van Cauter, published in the August 16 issue of the Journal of the American Medical Association, chronicled sleep patterns and HGH secretions in healthy men, charting changes that begin in the late 20s and early 30s. The documented drop in the growth hormone, researchers found, leads to increased fat tissue and abdominal obesity, reduced muscle mass and strength, and reduced exercise capacity. With the drop in HGH also comes a decrease in sleep: by the time men reach age 45, they have nearly lost the ability to fall into deep sleep, the stage when brain waves get slower and larger. After age 50, the average man's total sleep declined by about 27 minutes per decade of age. The research also showed that men who get less sleep, regardless of age, secrete less HGH.

"We actually know that if we increase deep sleep, we can increase growth hormone," says Van Cauter. "The appearance of a paunch belly can be delayed by a decade or two."

Van Cauter is currently testing an experimental drug to see if it will increase deep sleep, although researchers wonder if it will be worth the risk of medicating healthy people to slow natural aging.

Conducted only on healthy men, the experiment leaves questions about the effects of decreased deep sleep in women. In fact, pre-menopausal women do not appear to experience such a decline in deep sleep. Still, Van Cauter stresses the significance of quality sleep for everyone, female or male, old or young. "Having good sleep is something that should be right up there with priorities for maintaining good health." - B.C.