Abstract
OBJECTIVES: Physical activity is a key health behavior that reduces disease risk, and yet most older adults are not very active. This study examined time-varying associations between physical activity and a recognized barrier, namely, precipitation. And it examined the moderating role of physical activity intentions and functional mobility on precipitation-physical activity associations. METHOD: One hundred and twenty-six older adults (M age = 72 years; 64% women) from Metro Vancouver provided health and background information and wore triaxial accelerometers for up to 10 consecutive days. Daily weather information was collected from local weather stations. RESULTS: Multilevel models corroborate previous research by showing that older adults engaged in less physical activity on days with increased precipitation across four indices: activity counts, step counts, minutes of moderate to vigorous physical activity (MVPA), and bout-corrected minutes of MVPA. Older adults with strong physical activity intentions engaged in more physical activity overall. Physical activity intentions also modified the association between time-varying precipitation and activity counts and step counts, whereas functional mobility moderated the negative association between precipitation and activity counts and minutes of MVPA. DISCUSSION: Findings highlight the important role of time-varying influences on physical activity and how these associations are moderated by psychological and biological factors.