Secrets
Of
Sleep

Science & Society

A nation's wake-up call

By Bernadine Healy, M.D.

USN&WR Issue of May 17, 2004

Everyone should be a student of sleep, most especially one's own. In a world that never closes its eyes and has all but given up the proverbial day of rest, sleep is taken for granted. Some push off sleep as expendable; others brag about needing little of it, true or not. It's ironic that this attitude comes just as research is showing the intimate link between sleep and health. Beyond resting a weary body, slumber is a sanctuary to refresh, restore, reset, and replenish the mind; to foster creative thought and learning; and to inspire those early morning epiphanies that can solve the thorniest problems of the days gone by.

Almost everyone has experienced the misery of the swelling ranks of insomniacs who toss and turn, staring silently in the darkness, envious of those who do sleep. Surely there is no greater frustration than lying in bed, failing at sleep. Anxiety mounts as the clock ticks inexorably, sometimes the only sound in a sea of quiet overcome by fears that the next day will be dreary in payback for a sketchy sleep time.

To be sure, humans have figured out that insomniacs can get by in sleep-deprived fog. Our well-honed survival skills force momentary "microsleeps" to intrude on waking hours to compensate partially for brain fatigue. Chronic sleep deprivation nonetheless comes at the cost of fuzzy thinking, embarrassing daytime sleep attacks, depressed moods, and alterations in the body's endocrine and immune systems. And then there is the impaired performance of the sleep-worn working in risky fields like medicine or transportation, which have caused some needless accidents and harmed innocents.

Tyrannical clocks. Skimpy sleep, by intention or because our bodies can't seem to do better, inevitably demands payback, and the body's innate time clocks serve as scorekeeper. Our biological clocks are tyrants, compelling us to slumber away a third of our days, while independently keeping in sync with people and places around us. From controlled clockless sleep labs where subjects are free to wake and sleep to their hearts' content, we've learned that the natural human circadian cycle averages 25 hours, not 24. But what would otherwise be a biological pull to go to bed an hour later and sleep an hour longer every day is automatically quelled by the brain's ability to synchronize its internal clocks with the environment through external cues, such as light and the watch on our wrist. In fact, throughout one's lifetime, sleep patterns undergo changes that are sometimes beautiful and sometimes rocky but ever encouraging that sleep behavior can be modified.

Babies emerge from the darkness of the womb sleeping some 16 hours a day, with internal clocks that are completely out of whack with the world they're entering. Indeed,getting little ones on 24-hour sleep/wake cycles may be parents' first big struggle. It should be no surprise that our adolescents also go by their own time clocks. Teens generally run closer to a 26-hour cycle, which means they're programmed night owls of sorts. Explaining, of course, why they go out so late and sleep till noon. Getting these circadian renegades in sync with the real world poses yet another parental challenge.

But problems of sleep mostly show up in middle age and beyond. Sleep/wake cycles get shorter, which means older people are earlier to bed and earlier to rise. Though this carpe diem early-rising strategy is often contrasted with the sloth of the younger late-sleeping set, it's not necessarily a boon. The aging sleep pattern is marked by lighter, more fragmented sleep, and very little of the deep slow "delta wave" sleep that makes snoozing so enjoyable and restorative.Poetically, perhaps, it also comes with many fewer dreams. It should be no surprise that disturbed sleep is one of the most common health complaints doctors encounter as people age. And with the new specialty of sleep medicine, doctors are just beginning to understand and successfully manage a wide range of sleep-related problems.

What's still wanting, however, is a public-health rally like the ones that brought attention to the ravages of tobacco, the dangers of obesity, and the need for daily exercise. Let's face it: We arise every morning and do our jobs, but for want of sleep, not always as healthily or as safely as we could. It's time for a wake-up call to nudge our sleepy nation.