Sleep May Help Keep Metabolic Process Young

From the WebMD Archives

July 13, 2000 -- Those who must use an alarm to wake up share a common health problem: sleep deprivation. That's according to Mark Mahowald, MD, director of the Minnesota Regional Sleep Disorder Center in Minneapolis. The vast majority of Americans fit into the category, he says, and it's nothing to make light of. "Sleep debt is a major problem. ... It impairs performance whether we're aware of it or not."

And now, ongoing research suggests that getting a good night's sleep may play a crucial role in keeping people of all ages healthy, particularly the young.

"We can't say yet that sleep equals youth," says a researcher from the Van Cauter Laboratory in Chicago, who asked that WebMD not use his name. What they can say, based on lab research, is that sleep deprivation in more than 40 healthy 25- to 40-year-olds resulted in the "aging" of a metabolic process known as "glycemic control," or blood sugar control, so that it became identical to that of a 65- to 70-year-old's.

The change in blood sugar control was seen in those who slept less than six and a half hours a night. When they slept longer, their glycemic control returned to normal.

The study has not yet been published because it is not yet complete. But in light of its findings so far, the lab has a new question, the researcher says. "One of the associations we're pursuing is: Diabetes and obesity are epidemic, and is there a connection to sleep loss? Young, healthy subjects should not be getting problems with glycemic control for 30 years." In a similar vein, the Chicago researchers plan to study what effect that restoring sleep quality might have on glycemic control in diabetics who suffer from sleep apnea.

It's clear that getting enough sleep is important. But just how much sleep is enough? WebMD asked the experts and found a range of opinion on the matter.

The Van Cauter researcher says that from his lab's point of view, people need more than eight hours of sleep, but they're not sure what's enough. "It's more than currently thought," the researcher says. "We base that on two things: Do you want to be able to perform optimally and [have] optimal glycemic control?"


Mahowald has a different opinion. "The average sleep requirement is about seven and a half hours," he tells WebMD. "The range is between four and 10 hours. It's genetically controlled." He says that people can't "train" themselves to get by on less sleep because they have this genetic need for a certain amount.

One of the nation's best-known advocates for more sleep, William Dement, MD, sees it this way: "If you're feeling really tired [on arising], you should go back to sleep." Dement is director of the Stanford University Sleep Disorders Research Center.

But sleeping in can be an impossibility for those with jobs, families, and other responsibilities, and thus arose the great American tradition of "catching up" on sleep during the weekend. It can be done without spending all day in bed, Mahowald says.

"You only need to make up one-third of your loss. If you're six hours down for the week, you only need two more hours on the weekend." But the sleep debt payoff only works in one direction, he says. An extra two hours on Sunday isn't "bankable" for the week ahead.

Of course, there is a temporary cure for drowsiness, one that many people see as a vital part of their existence: caffeinated drinks. "For the short haul, caffeine will give you alertness," Mahowald says. The downside is that consuming caffeine late in the day may impair your sleep later that night.

Several drug treatments are available for those who have trouble getting to sleep at night, although none is foolproof. They include prescription drugs, over-the-counter medications and supplements, such as melatonin.

One researcher thinks there is excessive concern with sleep deprivation in America, and is suspicious about its source. Daniel F. Kripke, a professor of psychiatry at the University of California in San Diego, calls the idea of a national sleep debt "charming publicity," but he believes it's a myth largely perpetuated by drug companies seeking to sell more hypnotic sedatives, which induce a medium-deep sleep for relatively short periods of time.

These particular drugs are only approved for short-term use, but Kripke says drug companies want insomniacs to keep taking them. "In over 95% of studies of sleeping pill administration, either they make the next days' performance worse or they're of no benefit," he says.


But prescription medications, prescribed in select cases and used for brief periods of time, can be useful.

Julianne Carroll, a 30-year-old Atlanta resident, has had trouble sleeping since her teen-age years, and finally found relief with prescription drugs. She remembers how unsettling a string of several sleepless nights can be. "It was horrible. I was useless. I was emotional. I was walking around waiting for somebody to set me off."

Carroll tried several over-the-counter treatments to help her fall asleep. "But the side effects of these drugs were hard to live with, too. "They would help me sleep, and then I would be hung over in the morning. I walked around in a haze."

Mahowald, too, questions the benefits of these over-the-counter sleep aids, many of which contain antihistamines, such as diphenhydramine or doxylamine. "They make people feel sleepy, but they have never been shown to be truly beneficial in quality and quantity of sleep," he says. They also have some annoying and potentially dangerous side effects, including hangover, drowsiness, dry mouth, and an increase in mucus secretion in the throat.

Some people swear by supplements of melatonin, a hormone naturally secreted by the body's pineal gland as darkness falls. But the supplements are not regulated by the FDA, and at least one sleep expert is skeptical. "Melatonin is very controversial," says Dainis Irbe, MD, a neurologist at Egleston Children's Hospital in Atlanta. "I use it very, very seldom in patients."

There also are several non-drug options that may aid sleep. Experts suggest:

  • Using deep-muscle relaxation techniques or meditation.
  • Exercising, but not within a few hours of bedtime.
  • Avoiding alcohol and caffeine near bedtime, as well as late-night eating.
  • Using your bedroom only for sleeping and sex.
  • Leaving your bedroom if you can't get to sleep in 20 minutes of trying, and performing some quiet activity, such as reading.
  • Getting up at the same time each day.

Whatever method you choose, sufferers say it can be liberating to break the vicious cycle of sleeplessness. "Going to bed and fearing that you won't be able to sleep is a very stressful thing," Carroll says.

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