Abstract
BACKGROUND: There is a poor understanding of the dose-response relationship between years of physical activity and motor and cognitive function. We determined the dose-response effects of physical activity duration in years on motor and cognitive function and their relationship in healthy old females. OBJECTIVES: To determine the dose-effects of physical activity duration in years on motor and cognitive function and their relationship in health aging adults. METHODS: We conducted a retrospective observational study with 201 old (age 69 years; SD=5.9) and 12 young (mean age 21 years; SD=1.9) females, with sub-groups based on number of years of self-reported physical activity. Aerobic capacity, mobility, functional reach, standing balance, global cognition, episodic memory, executive function, and processing speed were assessed with performance-based tests. We analyzed sub-group differences quantitatively and qualitatively and performed regression and mediation analyses to determine predictors and mediators of physical activity effects. RESULTS: Based on physical activity of minimal (0.3 y, n=29), short (2.4 y, n=77), moderate (6.2 y, n=36) and long (16.6 y, n=59) duration, physical activity for at least 2.4 years affords old adults benefits in body mass index with peak dose-effects present in aerobic capacity and mobility at 6.2 years without additional benefits after 16.6 years of physical activity. Physical activity for any duration had no effects on functional reach, balance, executive function, episodic memory, and processing speed. Although weakly mobility predicted global cognition and executive function. CONCLUSION: Performing physical activity up to 6.2 years on average had favorable effects on body mass index, aerobic capacity and mobility. The data strengthen current recommendations for an active lifestyle in adulthood to prevent aging-related motor and cognitive decline.