Insufficient sleep is extremely prevalent in modern society with approximately one third of adults regularly getting less than 7 hours of sleep. Aerobic exercise, which is a mainstay to promote cardiovascular health, is commonly recommended also to improve sleep. Yet little is known on how it compares with other types of exercise in the general population. A new randomized trial suggests resistance exercise promotes better sleep than other workouts among inactive adults, particularly those who are poor sleepers. The trial results were presented at the recent Epidemiology, Prevention/Lifestyle & Cardiometabolic Health (EPI|Lifestyle) 2022 conference, which is sponsored by the American Heart Association (AHA) and took place on March 01-04 in Chicago.
A total of 406 inactive adults were recruited, aged 35 to 70 years, who were obese or overweight (mean body mass index, 31.2 kg/m2) and had elevated or stage 1 hypertension. They were randomly assigned no exercise or 60 minutes of supervised aerobic, resistance, or combination exercise three times per week for 12 months. The aerobic exercise group could choose among treadmills, upright or recumbent bikes, and ellipticals, and had their heart rate monitored to ensure they were continuously getting a moderate- to vigorous-intensity exercise. The resistance exercise group performed three sets of eight to 16 repetitions at 50% to 80% of their one-rep maximum on 12 resistance machines. The combination group did 30 minutes of aerobic exercise at moderate to vigorous intensity, and then two sets of eight to 16 repetitions of resistance exercise on nine machines instead of 12. Exercise adherence over the year was 84%, 77%, and 85%, respectively.
Participants also completed the Pittsburgh Sleep Quality Index (PSQI) at baseline and 12 months. Among the 386 participants (53% women) with evaluable data, 35% had poor-quality sleep, as indicated by a global PSQI score of more than 5, and 42% regularly slept less than 7 hours per night. In adjusted analyses, sleep duration at 12 months, on average, increased by 13 minutes in the resistance-exercise group (P = 0.009), decreased by 0.6 minute in the aerobic-exercise group, and increased by 2 minutes in the combined-exercise group and by 4 minutes in the control group. Among participants who got less than 7 hours of sleep at baseline, however, sleep duration increased by 40 minutes (P < 0.0001), compared with increases of 23 minutes in the aerobic group, 17 minutes in the combined group, and 15 minutes in the control group. It's unclear why the aerobic-exercise group didn't show greater gains, given the wealth of research showing it improves sleep, but this group had fewer poor sleepers at baseline than the resistance group (33% vs 42%).
