The Value of Daily Naps

By Dr. Gregg D. Jacobs

This study, published in a recent issue of the Journal of Sleep Research (2002; 11, 213-218) was conducted by Amber Tietzel and Leon Lack in Australia. The purpose of the study was to determine if short naps of 30 seconds, 90 seconds, and 10 minutes could improve alertness and cognitive performance in individuals whose sleep was restricted to five hours the preceding night. Each subject restricted their sleep to five hours on four nights and then took either a 30 second nap, 90 second nap, 10 minute nap, or no nap at 3:00 in the afternoon.

The findings from the study showed that the 10 minute afternoon nap significantly improved subjective alertness, fatigue and performance 30 to 60 minutes after the nap. However, the 30 second and 60 second naps did not improve alertness or performance. In conjunction with previous studies that have also demonstrated that naps can improve alertness and performance after sleep deprivation, this study suggests that a nap as brief as 10 minutes can reduce the effects of sleep loss.

These findings suggest that insomniacs and others who are sleep deprived can use naps to minimize the effects of sleep loss on daytime performance. However, several guidelines should be kept in mind when using naps in this fashion. First, limit naps to between 10-45 minutes in length. Longer naps may result in deep sleep which can disrupt nighttime sleep. Second, take a nap between 1:00-4:00 in the afternoon. Naps taken after 4:00 p.m. may also result in deep sleep which can disrupt nighttime sleep.