0174 Ninety-minute Recovery Nap Following Aerobic Exercise Improves Executive Function In Male Collegiate Students

The purpose of the present study was to examine the effects of a recovery nap following aerobic exercise on executive function. We further evaluated nap structure after aerobic exercise by using electroencephalography (EEG). In the first study, eight healthy, trained male volunteers (mean age, 21.9±0.4 years) performed a 90-min treadmill run at 60-65% of their heart rate reserve (HRR), starting at 8:45 am; they then participated in a counterbalanced measures design study under the following three conditions: 90-min of seated rest, and a 20-, and 90-min nap. A modified flanker (mFl) task consisting of congruent (i.e., “→ → → → →” or “←←←←←”) and incongruent tasks (i.e., “→ →←→ →” or “←←→←←”) was used for assessing executive function. Changes in oxyhemoglobin in the prefrontal cortex during the mFl task were monitored with near-infrared spectroscopy. Performance tests began at 15:00. In the second study, seven healthy, trained male volunteers (mean age, 21.9±0.4 years) participated in two experimental conditions (a crossover design study): 90 min seated rest and 90-min run on the treadmill at 60-65% of their HRR from 8:45 am. After that, participants took a nap between 12:30 and 14:00. During sleep, brain waves were measured using EEG. The 20-min nap group had shorter reaction times in the congruent task in a flanker task than the seated rest group. The 90-min nap group had shorter reaction times in the congruent and incongruent task of the flanker task. Increased oxyhemoglobin levels during the mFl task were observed in the left prefrontal cortex in the 20-min nap group and in the left and right prefrontal cortex in the 90-min nap group. We found that aerobic exercise decreased stage 1 sleep and increased slow-wave sleep in the 90-min nap group. The 90-min recovery nap shortened reaction times and increased activation of the prefrontal cortex in a flanker task. The increase in slow-wave sleep might, at least in part, play a role. This work was supported by an academic grant from the graduate school of Nippon Sport Science University.