Introduction: Poor sleep quality is associated with high blood pressure and elevated cholesterol, and regular short sleep (<7 hours) has been found to increase the risk of cardiovascular events. The American Heart Association recommends aerobic physical activity to improve sleep, although there are limited data on the effects of other popular types of physical activity, such as resistance exercise, on sleep.
Hypothesis: We hypothesized that 1 year of aerobic, resistance, and combined aerobic and resistance exercise would significantly improve sleep compared to a no-exercise control group.
Methods: Participants were 406 inactive adults (53% women, 35-70 years) with overweight/obesity and elevated/stage 1 hypertension at high risk of cardiovascular disease. They were randomly assigned to 1 of 4 groups: aerobic exercise (AE) only (n=101), resistance exercise (RE) only (n=102), combined AE and RE (CE) (n=101), and no-exercise control group (CON) (n=102) for 1 year. All exercise participants performed time-matched supervised exercise 3 times/week, 60 min/session (CE performed 30 min of each AE and RE), at 50-80% of their maximum intensity. Participants completed the Pittsburgh Sleep Quality Index (PSQI) at baseline and 12 months, and only participants with complete baseline data on all PSQI subscales were included (n=386). Primary outcomes were the PSQI total sleep quality score (lower scores = better sleep), sleep duration (hours), sleep efficiency (time asleep/time in bed), sleep latency (time to fall asleep), and sleep disturbances (a combination of the number and frequency of disturbances). Linear mixed effects models following the intention-to-treat principle were used to determine the effects of exercise groups on 12-month changes in sleep outcomes while adjusting for age, sex, and the baseline values of each outcome.
Results: Overall, 94% of participants completed the intervention with an 83% exercise adherence rate. The PSQI total score and sleep disturbances decreased significantly in all groups, including the control group. Within groups, sleep duration increased significantly by 17 minutes in RE (p=0.005), but not in AE (p=0.73; -2 min), CE (p=0.77; -2 min), or CON (p=0.13; -11 min), among participants getting less than 7 hours of sleep at baseline (p=0.02 for between-within groups interaction). Within groups, sleep efficiency increased in RE (p=0.0005) and CE (0.03), but not in AE (p=0.97) or CON (p=0.86; p=0.04 for between-within groups interaction). Sleep latency also decreased by 3 minutes in RE (p=0.003), although the overall between-within groups interaction effect was not significant (p=0.14).
Conclusions: These results indicate that resistance exercise may have superior benefits on sleep compared to aerobic exercise, which could provide a novel pathway for the role of resistance exercise in promoting cardiovascular health.