Effects of Aquatic Exercise on Sleep in Older Adults with Mild Sleep Impairment: a Randomized Controlled Trial

Exercise has been found to be associated with improved sleep quality. However, most of the evidence is based on resistance exercise, walking, or gym-based aerobic activity. This study aimed to examine the effects of an 8-week aquatic exercise program on objectively measured sleep parameters among older adults with mild sleep impairment. A total of 67 eligible older adults with sleep impairment were selected and randomized to exercise and control groups, and 63 participants completed the study. The program involved 2 x 60-min sessions of aquatic exercise for 8 weeks. Participants wore wrist actigraphs to assess seven parameters of sleep for 1 week before and after the intervention. Mixed-design analysis of variance (ANOVA) was used to assess the differences between groups in each of the sleep parameters. No significant group differences on demographic variables, life satisfaction, percentage of body fat, fitness, seated blood pressure, and any parameter of sleep were found at baseline. Significant group x time interaction effects were found in sleep onset latency, F(1,58) = 6.921, p = .011, partial eta squared = .011, and in sleep efficiency, F(1, 61) = 16.909, p < 0.001, partial eta squared = .217. The exercise group reported significantly less time on sleep onset latency (mean difference = 7.9 min) and greater sleep efficiency (mean difference = 5.9 %) than the control group at posttest. There was no significant difference between groups in change of total sleep time, wake after sleep onset, activity counts, or number and length of awakenings. An 8-week aquatic exercise has significant benefits on some sleep parameters, including less time for sleep onset latency and better sleep efficiency in older adults with mild sleep impairment.