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Shakespeare didn't need a scientific study to measure the value of sleep. Macbeth, fresh from fatally stabbing the king of Scotland, panics when he realizes he has also murdered slumber: "the innocent sleep, sleep that knits up the raveled sleave of care . . . sore labor's bath, balm of hurt minds . . . chief nourisher of life's feast."
Instinctively, you know this as well, even if you're not inclined to regicide. Given a big decision to mull over, you say, "Let me sleep on it," knowing that at some basic level sleep will produce a clearer state of mind. Science confirms this. Even though certain aspects of sleep remain a mystery, no one doubts its importance. In a recent study, laboratory rats deprived of sleep eventually died. Anyone who thinks we're dramatically different than rats -- physiologically speaking -- probably needs a good nap.
Yet our culture constantly does its best to cheat sleep. The invention of the mechanical alarm clock in 1876 and the electric lightbulb in 1879 set in motion a massive alteration of our natural sleep patterns. Today's 24/7 technology-driven world means we can stay up to grade stacks of essays or watch movies all night. Without good reason, we tend to admire people who boast they get by on four or five hours of sleep. Most people think of sleep (when they consider it at all) as wasted -- or, at the most -- empty time.
Nothing could be further from the truth. "Your brain is six to eight times more active when you're sleeping than when you're awake," says Richard D. Simon Jr., medical director of the Kathryn Severyns Dement Sleep Disorders Center, in Walla Walla, Washington. "Your brain diminishes stimulation to your muscles and senses, so you are not conscious of activity, but a lot is happening," he explains. For example, the endocrine system secretes hormones during sleep, and memory and learning are established.
Even the loss of one or two hours of sleep results in measurable negative effects on reaction times, the ability to learn and remember, alertness, and one's mood, according to Simon. Research is now under way to determine how sleep deprivation causes illness, or makes it worse. Well known is the part it plays in on-the-job injuries, driving accidents (100,000 automobile crashes each year happen when drivers are "asleep at the wheel," according to the National Institutes of Health), and just plain poor quality of life.
How much sleep do you need? Humans are hardwired to get an average of eight or eight and a half hours of shut-eye a night. Teenagers need even more -- nine to nine and a half hours a night, and younger children require ten or more hours of slumber.
But a National Sleep Foundation (NSF) poll this year found that, on average, adults sleep less than seven hours a night on weekdays and on weekends hit the pillow for only about thirty minutes more than that. About seven out of ten American adults have trouble sleeping a few nights a week or more, and more than one in three (37 percent) are so sleepy during the day that daily activities suffer.
What to do? An occasional sleepless night won't hurt you, but if you wake up feeling tired, or if you fight sleepiness at work and have little energy or patience, sleep (or lack thereof) may be the issue. See your doctor, and note whether you have trouble getting to sleep, or whether you wake up in middle of the night; you may have a sleep disorder as well.
In the end, says Simon, "sleep is not a lifestyle option. It's a life imperative." In fact, he adds, "we are awake in order to support sleep."