What you lose when you miss sleep

Nation's Business, Sept, 1992 by Christine K. Nowroozi

Managing well includes managing your own health; here is advice to help you do that better:

Of all our daily activities, sleep is often the easiest to sacrifice. Time spent sleeping, after all, can seem like time wasted. Actually, it's time invested--in sharp mental skills and alertness. And according to physicians and sleep researchers, it's an overlooked part of our health and well-being.

More than three-fourths of Americans wake up regularly to alarms, and almost as many sleep more than an hour or two longer on weekends than on weekdays. Both are signs of chronic sleep deprivation, experts say.

For years, these sleep researchers have told us that sleep deprivation--even in amounts we may consider insignificant--affects our ability to concentrate, work efficiently, and make sharp decisions.

Still, as Dr. William Dement, director of a sleep disorders clinic at Stanford University, in California, said in 1990 at a conference of family physicians, people "do not fully understand that daytime alertness is inevitably and solely linked to sleep at night." What we do understand, we often ignore.

"People who say they only need limited hours of sleep are just learning how to compensate by clenching their teeth," says sleep researcher Dr. Gary Richardson of Brigham and Women's Hospital in Boston.

Researchers don't know exactly how sleep loss affects people's health in the long run.

"We can't find a thing physiologically wrong with people who are sleep-deprived--even after three [or] four days of deprivation," says Dr. Wilse Webb, a psychologist at the University of Florida in Gainesville and author of a book called Sleep: The Gentle Tyrant (Anker).

But while the body as a whole is surprisingly unaffected, the brain shows significant effects. The ability to perform tasks that are well-learned or relatively quick in duration is generally preserved, Webb says, but the ability to perform tasks that "require you to intensively concentrate" gradually erodes.

One of the biggest myths about sleep, experts say, is that everyone needs a similar amount. To the contrary, individuals' sleep needs can vary from 4 1/2 to 10 hours a night. Very few people require fewer than 6 1/2 hours, though; around 65 percent of the population needs 6 1/2 to 8 1/2 hours, and almost everyone else needs more.

An hour or two less sleep than needed each night may not seem detrimental, but over the course of weeks and months such an accumulating debt can wreak havoc on adults, says Dr. Daniel R. Wagner of the Sleep-Wake Disorders Center at New York Hospital.

To some extent, sleep resembles a cheekbook that must be kept in balance. Trouble starts after age 30, as it becomes increasingly difficult to make up large sleep deficits. The body also has more difficulty adjusting to varied sleep times.

"The problem with trying to make up sleep on weekends," says Wagner, "is that, once past your teenage years, you lose the ability to extend sleep for many hours. You end up carrying your debt into the next week."

Changing our attitudes toward sleep, and appreciating the significance of sleepiness, are the first steps toward improving health and alertness. Here are some others:

* To determine your sleep requirements, experts suggest, you should keep track of the hours you sleep each night during a relaxed, week-long vacation. Then take the average.

* Also, take note of your sleeping patterns on weekends. If you're sleeping more than an hour or two extra, you definitely need more sleep at night. The same holds true if you regularly depend on your alarm clock.

* Varying your bedtime by an hour or so won't hurt, but keep your wake-up time steady.

* Don't rely on your own perceptions of your alertness, memory, concentration, and temperament; deterioration can be subtle. Listen to your colleagues or family.

* Take naps, but follow some rules. Never nap after 4 p.m., and don't nap for over an hour. Longer naps tend to be "replacement naps," which take you into the sleep state, rather than the "recreational naps" that are good for quickly boosting your alertness.

* When you travel across time zones, try not to reset your internal clock by more than two hours on any given day.

* If you are sleeping more than eight to 10 hours a night but you still experience daytime sleepiness (apart from the normal afternoon drowsiness), or if you consistently have trouble falling asleep, see your doctor. Most sleep disorders can be treated.