This is the 2007 version. Click here for the 2017 chapter 03 table of contents.

Normal and Disturbed Sleep

Many people have heard that 8 hours of sleep is normal. That is an average, but there are wide variations. In one study, 4000 entering freshmen at the University of Florida filled out questionnaires asking about sleep habits. Fewer than 50% averaged between 7.5 and 8.5 hours of sleep per night. 20% slept less than 7 hours, 5% more than 9 hours on the average. The overall average was 7.2 hours per night (Webb, 1981).

What unexpected finding turned up in research on U of Florida freshmen?

One way to compensate for loss of sleep is to take short naps. Leonardo da Vinci reportedly used this technique when staying up for long periods of time: he would catch a 15-minute nap every four hours. College students also nap frequently, according to a University of Florida study described by Webb (1981), "The amount of napping was far greater than expected." Only 16% did not nap in a two-week period. The average bedtime was 12:45 a.m., and the average wakeup time was 8:25. There were no significant male/female differences.

Webb wrote, "Just as there are tall and short people or people with big and little feet, there are natural short and long sleepers." He cited a case confirmed by laboratory studies: two Australian men who "slept consistently less than three hours per night." Contrary to earlier reports, there are no consistent personality differences between long sleepers and short sleepers.

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