Abstract
BACKGROUND: Physical activity (PA) is a promising strategy for the promotion of brain health, although substantial variation exists in the effects of PA at the individual level. Given the greater prevalence and faster progression of Alzheimer's disease in women compared to men, and known sex differences in brain architecture, analysis of sex differences in the relationship between PA, cognition, and brain region volumes is warranted. METHODS: To address this, we conducted secondary analyses of data from the Health, Aging, and Body Composition study. To determine whether longitudinal changes in PA over 10 years predicted declines in global cognitive functioning and executive functions and processing speed differently in males and females, latent growth curve modeling was utilized. Magnetic resonance imaging was performed at year 10, and the hippocampus and dorsolateral prefrontal cortex were identified as regions of interest. RESULTS: Maintaining PA over 10 years predicted less declines in executive functions and processing speed in females but not males. Maintaining PA over 10 years was significantly associated with greater volume of the left dorsolateral prefrontal cortex, a brain region involved in executive functions, in year 10 in females only. Maintaining physical activity was associated with better global cognitive function in both males and females, and also predicted volume of the left hippocampus, albeit in different directions with females showing a negative relationship and males showing a positive relationship. CONCLUSIONS: These findings suggest that the relationship of PA with cognition and its neurobiological correlates differ by sex, with females apparently benefiting from PA to a greater extent than males. Development of personalized, tailored exercise recommendations to promote healthy brain aging should account for sex differences.