Physical Activity and Trajectories of Cognitive Change in Community-Dwelling Older Adults: The Rancho Bernardo Study.

BackgroundAlthough physical activity has been associated with better cognitive function and reduced dementia risk, its association with cognitive decline in normal aging remains uncertain.ObjectiveTo determine whether physical activity in youth and older age are associated with age-related cognitive change.MethodsOver a period of 27 years, 2,027 community-dwelling adults (mean age 73.5; 60% women) of the Rancho Bernardo Study of Healthy Aging completed up to seven cognitive assessments, including tests of global cognitive function, executive function, verbal fluency, and episodic memory. At each visit, participants reported concurrent physical activity. At baseline (1988- 1992), participants additionally reported physical activity as a teenager and at age 30. For each age period, participants were classified as regularly active (3+ times/week) or inactive.ResultsAssociations between concurrent physical activity and better cognitive function were stronger with advancing age on all tests, even after accounting for education, health, and lifestyle factors, as well as survival differences (ps < 0.05). Baseline physical activity did not predict rates of cognitive decline (ps > 0.40). Individuals who were physically active at age 30 and older age maintained the highest global cognitive function with advancing age (p = 0.002).ConclusionRegular physical activity is associated with better cognitive function with advancing age. Physical activity in young adulthood may contribute to cognitive reserve, which together with physical activity in later years, may act to preserve cognitive function with age