Prospective study of physical activity and sleep in middle-aged and older adults.

INTRODUCTION Few prospective cohort studies have examined the association between physical activity (PA) and insomnia prevention, and the effective PA intensity remains unclear. This prospective study explores how PA intensity prevents incident short sleep duration and subjective insufficient sleep in middle-aged and older adults. METHODS A self-reported questionnaire gathered data on sleep and PA variables, including moderate low-intensity PA (MLPA); moderate high-intensity PA (MHPA); and vigorous-intensity PA (VPA), during health checkups conducted in Meiji Yasuda Shinjuku Medical Center in Tokyo. This study followed two cohorts from a 2008 baseline survey: (1) participants free of short sleep duration (n=7,061) and (2) participants free of insufficient sleep (n=7,385). They were divided into middle-aged (<60 years; 45.7 [8.8] years for sleep duration and 45.5 [8.8] years for sleep sufficiency) and older adults (both groups aged 65.3 [4.7] years) and followed for a mean 3.4 years until 2013. Data were analyzed in 2014. RESULTS Engaging in MHPA (hazard ratio [HR]=0.81, 95% CI=0.67, 0.98) and VPA (HR=0.83, 95% CI=0.71, 0.97) had a significant preventive effect on incident subjective insufficient sleep among middle-aged adults. For older adults, only MLPA (HR=0.58, 95% CI=0.42, 0.81) had a significant preventive effect on incident insufficient sleep, and PA did not significantly affect incident short sleep duration. CONCLUSIONS Middle-aged adults engaging in MHPA and VPA and older adults engaging in MLPA can effectively maintain sleep sufficiency. When providing an effective PA program to prevent insomnia, the intensity of PA should correspond to the participant's age.