Sleeping Your Way to the Top

By Sora Song

Americans are not renowned for their powers of self-deprivation; doing without is not something we do particularly well. But experts say there is one necessity of life most of us consistently fail to get: a good night's sleep.

The recommended daily requirements should sound familiar: eight hours of sleep a night for adults and at least an hour more for adolescents. Yet 71% of American adults and 85% of teens do not get the suggested amount, to the detriment of body and mind. "Sleep is sort of like food," says Robert Stickgold, a cognitive neuroscientist at Harvard Medical School. But, he adds, there's one important difference: "You can be quite starved and still alive, and I think we appreciate how horrible that must be. But many of us live on the edge of sleep starvation and just accept it."

Part of the problem is we are so used to being chronically sleep deprived--and have become so adept at coping with that condition--that we no longer notice how exhausted we really are. In 2003, sleep expert David Dinges and colleagues at the University of Pennsylvania School of Medicine tested the effects of restricting slumber to eight, six or four hours a night for two weeks. During the first few days, subjects sleeping less than eight hours admitted to being fatigued and lacking alertness. But by Day 4, most people had adapted to their new baseline drowsiness and reported feeling fine--even as their cognitive performance continued to plummet.

Over time, the experiment's sleep-restricted subjects became so impaired that they had difficulty concentrating on even the simplest tasks, like pushing a button in response to a light. "The human brain is only capable of about 16 hours of wakefulness [a day]," says Dinges. "When you get beyond that, it can't function as efficiently, as accurately or as well."

In the real world, people overcome their somnolence--at least temporarily--by drinking coffee, taking a walk around the block or chatting with office mates. But then they find themselves nodding off in meetings or, worse, behind the wheel. Those short snatches of unconsciousness are what researchers call microsleep, a sure sign of sleep deprivation. "If people are falling asleep because 'the room was hot' or 'the meeting was boring,' that's not coping with sleep loss. I would argue that they're eroding their productive capability," says Dinges.

What most people don't realize is that the purpose of sleep may be more to rest the mind than to rest the body. Indeed, most of the benefits of eight hours' sleep seem to accrue to the brain: sleep helps consolidate memory, improve judgment, promote learning and concentration, boost mood, speed reaction time and sharpen problem solving and accuracy. According to Sonia Ancoli-Israel, a psychologist at the University of California at San Diego who has done extensive studies in the aging population, lack of sleep may even mimic the symptoms of dementia. In recent preliminary findings, she was able to improve cognitive function in patients with mild to moderate Alzheimer's simply by treating their underlying sleep disorder. "The need for sleep does not change a lot with age," says Ancoli-Israel, but often because of disruptive illnesses and the medications used to treat them, "the ability to sleep does."

If you're one of the otherwise healthy yet perpetually underrested, there's plenty you can do to pay back your sleep debt. For starters, you can catch up on lost time. Take your mom's advice, and get to bed early. Turn off the TV half an hour sooner than usual. If you can't manage to snooze longer at night, try to squeeze in a midday nap. The best time for a siesta is between noon and 3 p.m., for about 30 to 60 minutes, according to Timothy Roehrs, director of research at the Sleep Disorders and Research Center at Henry Ford Hospital in Detroit. He advises against oversleeping on weekend mornings to make up for a workweek of deprivation; late rising can disrupt your circadian rhythm, making it even harder later to get a full night's rest.

According to Dinges' analysis of data from the 2003 American Time Use Survey, the most common reason we shortchange ourselves on sleep is work. (The second biggest reason, surprisingly, is that we spend too much time driving around in our cars.) But consider that in giving up two hours of bedtime to do more work, you're losing a quarter of your recommended nightly dose and gaining just 12% more time during the day. What if you could be 12% more productive instead? "You have to realize that if you get a good night's sleep, you will actually be more efficient and get more done the next day. The more you give up on sleep, the harder it is to be productive," says Ancoli-Israel. "What is it going to be?"

If mental sharpness is your goal, the answer is clear: stop depriving yourself, and get a good night's sleep.