Directionality between cognitive function and daily physical activity patterns.

Introduction: Physical activity is a modifiable risk factor for dementia, but cognitive function is also important for physical activity engagement. This study evaluated the directionality of associations between daily physical activity and cognitive function in a sample of cognitively and physically intact older adults.

Methods: Cognitive factor scores for domains including global cognition, memory, language, executive function/attention, and visuospatial processing, and physical activity patterns from wrist accelerometry were measured at two visits (mean: 1.8 years) among 237 cognitively intact older adults in the Baltimore Longitudinal Study of Aging (BLSA) (mean age: 76.5 years). Bivariate latent change score models estimated directionality of associations between changes in cognitive factor scores and physical activity patterns. Models were adjusted for age, sex, race, education, comorbidities, and body mass index.

Results: Higher total amount of activity, longer activity bouts, less sedentary time, and less activity fragmentation at baseline were associated with less annual cognitive decline across multiple cognitive domains ( > 4.11, 1 df for all). In contrast, baseline cognitive factor scores were not associated with changes in any activity pattern (  < 3.20, 1 df for all).

Discussion: Increasing movement and/or decreasing sedentary behavior is associated with less prospective cognitive decline. Targeting reductions in sedentary time and lengthening activity bouts may slow cognitive decline among older adults at risk for dementia.

Highlights: Greater activity engagement is related to less annual cognitive decline.Baseline cognition is not associated with short-term changes in activity patterns.Promoting daily movement and lowering sedentary time may have cognitive benefits.