Catching enough ZZZZs for good health

Sleep deprivation linked to increased risk of obesity, heart problems and more

October 13, 2006|By Susan Brink | Susan Brink,Los Angeles Times

The alarm clock in Thom Stys' bedroom goes off at 4 a.m. every weekday, a scant four to five hours after his head hits the pillow. By 5 a.m., he's left his home, and before the sun is up, he's at his desk in Long Beach, Calif., making a round of phone calls to clients in Europe.

"If I left later, it would take me an hour and a half to get to work," says the 57-year-old vice president of an aerospace forging company. "I simply can't afford to spend time caught up in freeway traffic."

Most working blokes know that the more they work, the less they sleep. What they may not know is that the more time they spend in their cars, the less they sleep. Drive time - not television viewing, computer addiction or exercise - is second only to hours on the job as a reason people don't get the shut-eye they need.

"The most deadly combination," says David F. Dinges, chief of the division of sleep and chronobiology at the University of Pennsylvania School of Medicine, "would be long commute time, long work hours and living in a place where you have to get in the car and drive to get anything."

Sound like home?

The combination is deadly because a good night's sleep appears to be every bit as important to good health and long life as a nutritious diet and regular exercise. "Sleep is in the top three," Dinges says. "And I think it's No. 1. Sleep is a biological imperative and not getting enough has health-related costs."

In April, the Institute of Medicine issued a report confirming links between sleep deprivation and an increased risk of hypertension, diabetes, obesity, depression, heart attack and stroke.

Some scientists are exploring possible connections between inadequate sleep and a decline in immune function.

The Archives of Internal Medicine devoted its Sept. 18 issue to the relationship between sleep and health. An editorial called for assessment of sleep habits as a standard part of all medical checkups.

That's because short sleep can hasten the arrival of the inevitable long sleep. The largest study of sleep duration and mortality was published in February 2002 in the Archives of General Psychiatry. The Cancer Prevention Study II of the American Cancer Society followed more than a million participants for six years.

The best survival was found among those who slept about seven hours a night, the worst among those who slept less than 4.5 hours. Too much sleep - nine hours or more - also was associated with a higher risk of mortality.

In the past decade, researchers have begun studying sleep based on today's reality: a country open for business virtually 24/7, and a populace increasingly unwilling or unable to call it a day. Sleep needs vary slightly, but the vast majority of people, experts agree, need just about eight hours of sleep each night to fully recover from 16 hours of being awake.

About 40 percent of Americans say they get fewer than seven hours of sleep on weekdays, and 71 percent get fewer than eight hours of sleep, according to a 2005 survey by the National Sleep Foundation. Even on weekends, they sleep about 7.4 hours.

Cost of lost sleep

Sleep researchers have a name for the way the majority of people in this country sleep: volitional chronic sleep deprivation, and it is a lifestyle disorder.

Without enough sleep, the cost in reduced memory, focus, concentration and reaction time is well established.

But it's only in the past half-dozen years that studies have begun to link chronic partial sleep deprivation to serious physical health consequences.

Sleep is essential to the workings of every organ. And it seems that the connection between sleep and health starts at the brain's central command post, the hypothalamus. There, sleep or lack of it can work to activate, or inhibit, hormone production. There, too, is where the body gets the signal to go to bed, to wake up and to adjust temperature, blood pressure, digestive secretions and immune activity.

Inadequate sleep works on hormone production in other areas as well. Without enough sleep, the central nervous system becomes more active, inhibiting the pancreas from producing adequate insulin, the hormone the body needs to digest glucose.

A groundbreaking study in 1999 led by Eve Van Cauter, a professor of medicine at the University of Chicago, showed that just six days of sleep restricted to four hours pushed 11 healthy young male volunteers into a pre-diabetic state. Those jaw-dropping results expanded the field of sleep research and convinced scientists that chronic, partial sleep deprivation damaged the body, not just the mind.

The young men in the same study also had reduced levels of the stress hormone cortisol, which normally surges just before waking from a good night's sleep, energizing people for the day's demands. The study participants had the low morning levels of cortisol typical of their grandparents.

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