THE ENCHANTED WORLD OF SLEEP.

#### THE ENCHANTED WORLD OF SLEEP.

By Peretz Lavie. Translated by Anthony Berris. Yale Univ. Press. 288 pp. $27.50

#### SLEEP THIEVES: An Eye-Opening Exploration Into the Science & Mysteries of Sleep.

By Stanley Coren. Free Press. 304 pp. $24

"The only way to make money is to be awake all the time." Sleep is a waste of time, according to this busy manager of a mutual fund quoted in Sleep Thieves by Stanley Coren, professor of psychology at the University of British Columbia. Both Coren and Peretz Lavie, the author of The Enchanted World of Sleep, dispute the proposition that we should sleep less. In their complementary books, they argue persuasively that we are a sleep-deprived society. Attempts to save time by not sleeping result in a continuum of disturbances ranging from daytime drowsiness to mental illness.

Both books provide excellent overviews of what we know and need to know about sleep. Lavie, dean of the Faculty of Medicine and director of the Sleep Laboratory at Technion-Israel Institute of Technology in Haifa, takes a more scholarly approach. He stresses the biological aspect of sleep and reports on a number of fascinating experiments. One of the most remarkable is his own 1991 sleep laboratory study of Holocaust survivors.

Lavie studied the sleep of three groups: survivors with good family and occupational adjustments; survivors with poor adjustments; and a control group of native-born Israelis. Not surprisingly, the well-adjusted survivors resembled the control group in falling asleep easily and displaying the rapid eye movement (REM) that indicates dreaming. But when awakened during REM sleep, the well-adjusted survivors could recall only 33 percent of their dreams—the lowest figure ever reported. (The control group recalled 78 percent, the poorly adjusted survivors 55 percent.) This suggests a striking—and unexpected—continuity between the mental processes of dreaming and the psychological defenses that protect the waking mind against traumatic thoughts and memories.

Coren’s chief concern is with sleep deprivation. The natural pattern of human behavior, he argues, is work during the day, recreation during the evening, and sleep at night. So ingrained is this pattern that fully 20 percent of shift workers voluntarily give up their jobs rather than suffer the physical and mental consequences of having their "normal sleep-wakefulness cycle" disrupted.

Sleep deprivation leads to problems beyond loss of employment. Each spring, when we lose an hour of sleep changing to daylight-saving time, the death rate from automobile accidents in the United States jumps seven percent. In the fall, when we gain an hour, the pattern is reversed. Observes Coren: "As a society we must be running a fairly heavy sleep debt if the loss of one hour more of sleep can make it seven percent more likely that we will have a mishap on the road."

On how much sleep we actually need, the authors differ. Lavie states that five or six hours is enough if the individual "is alert and energetic during the day, and does not feel either chronic fatigue or a strong desire to sleep." Coren disagrees. He finds that "our normal efficiency, alertness, and creativity is not as good with eight hours of sleep as it is with 10."

Thus we face a conundrum: like the mutual fund manager, we want to use our time most efficiently. Yet to function at an optimal level, we need to invest more time in a reputedly inefficient, self-indulgent activity. "It is truly an odd feature of our society that short sleepers are idolized," writes Coren. "Today the person who runs on little sleep is seen as mentally tough, ambitious, and admirable." It’s hard to imagine a successful person in any field advising a junior counterpart to get more sleep. Yet that may be just the right prescription. Both of these books underscore the point made by Aldous Huxley: "That we are not much sicker and much madder than we are is due exclusively to that most blessed and blessing of all natural graces, sleep."

—Richard Restak