The effects of a 20‐min nap before post‐lunch dip

Abstract The effects of a 20‐min nap before post‐lunch dip were studied. The subjects participated in nap and no‐nap conditions at intervals of 1 week. Their electroencephalogram (EEG) recordings of relaxed wakefulness, mood, performance, and self‐rating of performance level were measured every 20 min from 10.00 to 18.00 h. For nap condition, the subjects went to bed at 12.20 h and were awakened after they slept for 20 min. The nap improved subjective sleepiness and self‐rating of task performance, and suppressed EEG alpha activity. The results suggest a positive effect of a 20‐min nap upon the maintenance of daytime arousal level.