New Research Links Good Sleep to Good Health

The country’s financial woes have found their way into the bedroom.

Poll results released by the National Sleep Foundation (NSF) in early March find that one-third of Americans are losing sleep over worries about the economy, personal finances and health care costs. The restless nights might be harming their health as well.

It’s no secret that sleep is essential to health—it rests the body, renews the brain and produces higher levels of certain beneficial hormones. Unfortunately, getting those often-recommended seven to eight hours of sound, restful sleep—night after night—may be something you can only dream about.

By around age 60, it may take even longer to fall asleep—and stay asleep. The NSF says that nearly half of older people report they have insomnia several nights a week or more.

Sometimes, bad sleep is the result of health conditions—from those midnight bathrooms breaks triggered by an enlarged prostate to the pain of arthritis, fibromyalgia and other ailments. But even perfectly healthy people in their later years may find themselves dosing off in the daytime and tossing and turning at night.

“As you age, different physiologic processes take place in the body that affect sleep,” explains Aparajitha Verma, M.D., medical director of the Sleep Disorders Center at the Methodist Hospital in Houston. “The circadian rhythm of older people—your internal body clock—changes, so you may be sleepier in the daytime and have lower sleep efficiency at night.”

But that may be OK, say some experts. In one study published last August in Current Biology, researchers from Harvard’s Brigham and Women’s Hospital and from the United Kingdom reported that otherwise healthy people sleep less as they get older because they need less shuteye—about 1.5 hours less per night for those in their 60s compared with twentysomethings. Why less sleep? Because of a shifting circadian rhythm, more daytime napping and, often, a lower daytime expenditure of energy.

“Some people need more sleep, some people need less: A specific person’s individual sleep requirement is just that—very individual,” notes Verma. “But for most people, it’s clear that not getting seven or eight hours a night consistently is related to several health issues such as problems with memory, concentration and learning; poorer physical performance; and a greater risk of traffic accidents.”

But in recent months, several studies provide more evidence that failing to consistently meet the goal of seven to eight hours may further impact some already dangerous age-related conditions:

Blood vessels. Artery-stiffening calcium deposits are twice as likely to occur in people who sleep five to seven hours per night, finds a study published last December in the Journal of the American Medical Association that tracked 495 middle-age men and women for five years. But increasing sleep just one hour per night may cut this risk by about a third—the equivalent of a 16-point drop in blood pressure.

The links between sleep and artery health are still being explored but senior researcher Diane Lauderdale of the University of Chicago has some theories. “Blood pressure tends to dip during sleep, so it’s possible that sleeping longer means that people have relatively lower blood pressure during a 24-hour period,” she says. “Also, when people are sleep deprived, that may release high levels of stress hormones such as cortisol, which we know is a risk factor for heart disease.”

Cholesterol. It’s not clear why, but older people who sleep less than seven hours per night—or more than eight hours—may have higher cholesterol, and lower levels of heart-healthy HDLs, observed Dutch researchers in the November/December 2008 issue of Psychosomatic Medicine. Their study included 768 men and women age 57 and older, none of whom were taking statin drugs.