The effects of a 20-min nap at noon on sleepiness, performance and EEG activity

Int J Psychophysiol. 1999 May;32(2):173-80. doi: 10.1016/s0167-8760(99)00009-4.


The prophylactic effects of a 20-min nap at noon on afternoon sleepiness were studied. Ten young adults who had normal sleep-wake habits without habitual daytime napping were subjected to nap and no-nap conditions at an interval of 1 week. After a nocturnal sleep recording (00.00-08.00 h), their EEG recordings during relaxed wakefulness, mood, performance, and self-ratings of performance level were measured every 20 min from 10.00 h to 18.00 h. For the nap condition, they went to bed at 12.20 h and were awakened when 20 min had elapsed from the onset of sleep stage 1. For the no-nap condition, they rested without sleeping by sitting on a semi-reclining chair. The nap did not improve task performance, however, it improved volition and the self-rating of task performance. It also suppressed subjective sleepiness and attenuated eyes-opened EEG alpha activities. The results suggest that a 20-min nap at noon had partial positive effects on the maintenance of the daytime arousal level.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Affect / physiology*
  • Alpha Rhythm / psychology*
  • Female
  • Humans
  • Male
  • Rest / physiology
  • Rest / psychology*
  • Sleep / physiology*
  • Time Factors