Jan. 15, 2007 issue - Philippines: As I get older (I'm 50), I notice I like to take afternoon naps. Is this normal? I exercise regularly, eat well and am not overweight. Dr. Harvey Simon: Daytime sleepiness can result from insufficient nighttime sleep. Causes range from simply not devoting enough time to sleep to medical conditions that impair the quality of sleep, including restless-leg syndrome and obstructive sleep apnea. And in some cases, daytime sleepiness can result from medical problems such as depression or an underactive thyroid.
Fortunately, your situation sounds completely different. People who are sleep-deprived feel groggy during the day and may fall asleep when they least want to, at their desks or behind the wheel. Voluntary napping, on the other hand, is not a sign of sleep deprivation, illness or aging. In fact, a "power nap" can be helpful as well as enjoyable.
Federal researchers studied 200 airline flight crews that each conducted eight 9-hour transpacific flights during a span of 12 days. Half the crews stayed awake as usual, while the others took 40-minute naps in rotation. Napping was shown to improve subsequent alertness and performance. Many studies of shift workers and other volunteers have found that a nap as brief as 20 minutes can improve alertness, psychomotor performance and mood. Naps, however, can produce problems of their own. One problem is grogginess and disorientation that may accompany awakening from deep sleep. The second potential problem is nighttime wakefulness.
To get the benefit of a quick snooze, plan your nap at a good time in your daily sleep-wake cycle; for many people, sometime between noon and 4 p.m. is best. Don't sleep too long; a 20- to 40-minute nap may refresh you without keeping you up at night. And give yourself 10 to 15 minutes to wake fully before you resume a demanding task.
