Effects of intensity, frequency, and time window of exercise on sleep quality among community-dwelling adults aged 65–86 years

Background Although the effects of exercise training (ET) on sleep problem have been reported, the effects according to the components of exercise, including intensity, frequency, and time window, are unknown. Thus, in this study, we aimed to assess the effects of ET on sleep quality in community-dwelling older adults with sleep problems. Methods We evaluated individuals aged ≥65 years whose Pittsburgh sleep quality index was >5 points at baseline. The participants were allocated to either the control group or the ET group and underwent interval walking training (IWT) for 5 months. Information regarding intensity, frequency, and time window of ET were obtained using a waist-worn accelerometer. Results Overall, 63 participants (24 men [mean±standard deviation age: 75.1 ± 4.6 years] and 39 women [74.7 ± 5.2 years]) and 65 participants (24 men [75.2 ± 4.0 years] and 41 women [73.6 ± 4.2 years]) were included in the ET and control groups, respectively. The change in Pittsburgh sleep quality index was not significantly different between the two groups for both sexes. In the ET group, women who exercised 3–8 hours before bedtime, men who did ET >8 hours before bedtime and more than 1 hour after waking up, and men who did ET ≥5.05 days/week experienced significant improvements compared to the baseline. Conclusions IWT does not significantly improve sleep quality. To obtain improvements in sleep quality, it might be necessary to consider the time window of performing ET for both sexes and ET frequency for men.