P096 The Effect of Moderate-Intensity Exercise on Sleep Quality and Quantity in Healthy Adult Males

Abstract Introduction Acute exercise may have the ability to disrupt sleep in healthy adults. Given the popularity of afternoon exercise, it is important to determine how this affects sleep. Therefore, the aim of this study was to investigate the effect of afternoon moderate-intensity cycling exercise on objective and subjective sleep in healthy adult males. Methods To assess the effect of moderate-intensity afternoon exercise on sleep quality and quantity, 12 healthy adult males who were identified as good sleepers completed a repeated-measures, counter-balanced, crossover study design with two conditions (moderate-intensity aerobic exercise or no exercise). The exercise task involved cycling for 40 minutes at 70%HRmax and was completed ~15:30h. Polysomnography was used to measure sleep during a 9-h sleep opportunity (23:00h to 08:00h). Results There were no statistically significant differences in objective or subjective sleep between conditions. Exercise had a medium-sized effect on reducing total sleep time (mean ± SD; control 493.71 ± 12.59 mins vs exercise: 471.46 ± 55.19 mins; Cohen’s d: 0.56), sleep efficiency (mean ± SD; control 91.43 ± 2.33 % vs exercise: 87.31 ± 10.22 %; Cohen’s d: 0.56), and increasing REM onset latency (mean ± SD; control: 76.13 ± 45.10 mins vs exercise: 102.75 ± 46.85 mins; r: -0.33) (all p > 0.05). Discussion Healthy adult males can complete afternoon moderate-intensity exercise without compromising subsequent sleep. Individual responses in objective sleep outcomes may vary after exercise.