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

Author(s): Ito, S., Hori, T.

Journal/Book: Int J Psychophysiol. 1999; 32: PO Box 211, 1000 AE Amsterdam, Netherlands. Elsevier Science Bv. 173-180.

Abstract: 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.

Note: Article Hayashi M, Hiroshima Univ, Fac Integrated Arts & Sci, Dept Behav Sci, Kagamiyama 1-7-1, Higashihiroshima 7395821, JAPAN

Keyword(s): nap; post-lunch dip; daytime sleepiness; performance; vigilance; EEG alpha activity; CAFFEINE

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