Losing Sleep: How Your Sleeping Habits Affect Your Life

By Lydia Lotto

(William Morrow, New York); 342 pp.; $21.95

We don't often think of the electric light bulb, the jet engine and the conveyor belt as the "curses" of our time, but Lydia Lotto says that's exactly what they are.

The electric light bulb makes it possible for people to work -- and play -- all night. The jet engine has given us jet lag. The continuous conveyor belt has brought us shift work. And all three developments have helped break down the built-in clocks that used to govern people's lives. They have moved us farther and farther from our ecological niche and increasingly separated us from our natural rest/activity cycle dictated by the sun. We have let our "workaholic, achievement-oriented, time-obsessed culture" bollix up our circadian rhythms. That's why chronic fatigue and daytime sleepiness have become common.

Lotto, a Canadian science writer, has examined the research on sleep and repackaged it, carefully documented, for non-scientists. Although sometimes repetitive, her book is a wonderful repository for everything anybody ever knew about sleep.

What is sleep? Lotto says it remains a mystery, and although researchers can measure everything from eye movements to changes in oxygen levels in the blood, they still don't know why we engage in the complicated, time-consuming process.

Is sleep time out? Or a major restorative function? Muscles relax and recover when we rest as well as when we sleep, but apparently the brain needs the "shutdown" sleep provides. People who stay in bed 24 hours need just as much sleep as people who are up and about, according to Lotto.

Nobody can figure out why we need two kinds of sleep: Rapid Eye Movement (REM) sleep, during which the eyes dart rapidly, and non-REM sleep, which includes light sleep or drowsiness, intermediate sleep and ultimately deep sleep.

Most dreaming occurs during REM sleep. Richard Coleman, a California sleep researcher, has said that the brain works like a computer, in which files are reorganized, updated and erased; REM sleep may be the way the brain handles housekeeping. It would be difficult to update our memory bank while we were awake and functioning, Coleman says.

Francis Crick, the Nobel prize-winning molecular biologist, has gone further, suggesting that REM sleep is "reverse learning," that allows us to "unlearn" or discard useless or disturbing thought patterns and therefore prevent overloading the brain's storage capacity. It's not a good idea, according to this theory, to try to remember dreams because this could result in holding onto the thought patterns the brain is trying to throw out. Of course, this contradicts Freudian and Jungian doctrines, which state that remembering dreams is critical to psychological health.

Lotto's section on the 24-hour circadian rhythms contains some of the most interesting material in the book. We start life and end life, she says, with our circadian rhythms in disarray, as anyone who has ever tried to get a newborn on a schedule can attest to.

In the years between infancy and old age, when circadian rhythms are firmly established, most of us are most alert and the least sleepy at two times during the 24 hours -- in midmorning and early evening. Experiments in sleep laboratories have shown that most people without sleep disorders find it very difficult to fall asleep between 7 p.m. and 9 or 10 p.m., even if they're in a sleep-deprived condition.

The strongest circadian pressure for sleep occurs between 3 a.m. and 6 a.m., a forbidden "wake-up" zone in the 24-hour cycle. Another "trough," when many people get really sleepy, comes in mid-afternoon. But it's a built-in desire for sleep and not dependent on a big lunch or anything else. Lotto offers two tips: do memory-related jobs in the morning, and don't plan important conferences for the mid-afternoon trough.

Sleep clinics have been around for about 20 years, and researchers have come up with masses of information. For instance, the elderly and the poor are more apt to suffer from insomnia. (The young and rich have stronger social support systems.) Insomniacs sleep more than they think they do. In one study, insomniacs asked to keep a journal of how much they slept reported an average of 4.5 hours a night. When they slept in the laboratory, researchers found they averaged 6.5 hours.Scientists still can not say how much sleep people need, but the feeling seems to be that most of us don't get enough. Thomas Edison, who invented the light bulb, was famous for saying he needed only four or five hours of sleep. But he took naps -- lots of them. Sleep researchers have found that naps can be helpful, and studies show that even a little sleep is better than none.

Jet lag creates problems. Lotto cites a diplomatic agreement bungled because John Foster Dulles began negotiations right after he stepped off a flight from the U.S. And pilots must land planes on Europe-bound flights when they're in the circadian trough, between 3 and 6 a.m.

The implications for the workplace are considerable. Lotto notes that the near meltdown at Three Mile Island nuclear plant in 1979 began just after 4 a.m., the result of human error on the part of a crew that had been on the overnight shift for only a few nights. The Chernobyl nuclear accident also occurred in the morning's early hours.

Lotto quotes several studies that decry the lengthening hours people work and the decrease in leisure time. "An active, mentally demanding 16- to 18-hour day has become the expected norm," says Mortimer Mamelak, director of the Sleep Disorders Centre of Sunnybrook Medical Centre in Toronto.

"Many people have to be alert and going at top speed for immensely long hours. For every person who wants to sleep more, there is another trying to do with even less . . . Too many of us are overtired and overstimulated when we finally get to bed, and we then allow too little time for sleep."Ann Waldron is a writer in Princeton, N.J.