Physical activity, common brain pathologies, and cognition in community-dwelling older adults

Objective To examine the associations of physical activity, Alzheimer disease (AD), and other brain pathologies and cognition in older adults. Methods We studied 454 brain autopsies from decedents in a clinical-pathologic cohort study. Nineteen cognitive tests were summarized in a global cognitive score. Total daily physical activity summarized continuous multiday recordings of activity during everyday living in the community setting. A global motor ability score summarized 10 supervised motor performance tests. A series of regression analyses were used to examine associations of physical activity, AD, and other brain pathologies with global cognition proximate to death controlling for age, sex, education, and motor abilities. Results Higher levels of total daily activity (estimate 0.148, 95% confidence interval 0.053–0.244, SE 0.049, p = 0.003) and better motor abilities (estimate 0.283, 95% confidence interval, 0.175–0.390, SE 0.055, p Conclusions Physical activity in older adults may provide cognitive reserve to maintain function independent of the accumulation of diverse brain pathologies. Further studies are needed to identify the molecular mechanisms underlying this potential reserve and to ensure the causal effects of physical activity.