Sleep Deprivation, Disorders, and Drugs

Sleep Deprivation, Disorders, and Drugs

Many changes occur in the body during sleep. This section introduces you to the major ones.

Three Standard Psychophysiological Measures of Sleep There are major changes in the human EEG during the course of a night’s sleep. Although the EEG waves that ac- company sleep are generally high-voltage and slow, there are periods throughout the night that are dominated by low- voltage, fast waves similar to those in nonsleeping individuals. In the 1950s, it was discovered that rapid eye movements (REMs) occur under the closed eyelids of sleepers during these periods of low-voltage, fast EEG activity. And in 1962,

Most of us have a fondness for eating and sex—the two highly esteemed motivated behaviorsdiscussed in Chapter 12 and 13. But the amount of time devoted to these behaviors by even the most amorous gourmands pales in comparison to the amount of time spent sleeping: Most of us will sleep for well over 175,000 hours in our lifetimes. This extraordinary com- mitment of time implies that sleep fulfills a critical biolog- ical function. But what is it? And what about dreaming: Why do we spend so much time dreaming? And why do we tend to get sleepy at about the same time every day? Answers to these questions await you in this chapter.

Almost every time I lecture about sleep, somebody asks “How much sleep do we need?” Each time, I provide the same unsatisfying answer: I explain that there are two fun-

damentally different answers to this question, but neither has emerged a clear winner.

One answer stresses the presumed health-promoting and recuperative powers of sleep and suggests that people need as much sleep as they can comfortably get—the usual prescription being at least 8 hours per night. The other answer is that many of us sleep more than we need to and are consequently sleeping part of our life away. Just think how your life could change if you slept 5 hours per night instead of 8. You would have an extra 21 waking hours each week, a mind-boggling 10,952 hours each decade.

As I prepared to write this chapter, I began to think of the personal implications of the idea that we get more sleep than we need. That is when I decided to do some-

thing a bit unconventional. I am going to participate in a sleep-reduction experiment—by trying to get no more

than 5 hours of sleep per night—11:00 P.M. to 4:00 A.M.— until this chapter is written. As I begin, I am excited by the prospect of having more time to write, but a little worried that this extra time might cost me too dearly.

It is now the next day—4:50 Saturday morning to be exact—and I am just sitting down to write. There was a party last night, and I didn’t make it to bed by 11:00; but considering that I slept for only 3 hours and 35 minutes, I feel quite good. I wonder what I will feel like later in the day. In any case, I will report my experiences to you at the end of the chapter.

The following case study challenges several common beliefs about sleep. Ponder its implications before pro- ceeding to the body of the chapter.

The Case of the Woman Who Wouldn’t Sleep Miss M . . . is a busy lady who finds her ration of twenty- three hours of wakefulness still insufficient for her needs.

356 Chapter 14 ■ Sleep, Dreaming, and Circadian Rhythms

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