Associations between cognitive change and objective change in physical activity among older adults: the life study

Abstract Objective To investigate the associations between domain-specific cognitive change and objectively measured change in physical activity in a sample of community-dwelling older adults. We hypothesized that domain-specific changes in cognition are associated with longitudinal changes in physical activity levels. Methods We used data from 955 participants from The LIFE Study, a multi-center randomized clinical trial. Longitudinal relationships between cognitive domains (i.e., memory, attention, processing speed, executive function) and accelerometer-measured change in daily minutes of physical activity were examined using multivariable linear regression. Cognitive tests included Modified Mini-Mental State Examination (3MSE), Hopkins Verbal Learning Test (HVLT), Digital Symbol Substitution Test (DSST), Task Switching Test, Eriksen Flanker Test and N-Back Test. Physical activity was measured longitudinally using an accelerometer and was categorized to total, light, and moderate to vigorous according to standardized activity count cut points. Results Our results showed an association between cognitive change in the processing speed domain and change in minutes of total (β = 0.47; 95% CI: 0.04, 0.89; p = 0.034) and light (β = 0.42; 95%CI: 0.03, 0.80; p= 0.033) physical activity. Relationships between all other cognitive assessments and physical activity categories were not statistically significant. Conclusions This study demonstrates an association between a decline in processing speed and a decline in the duration of total and light daily physical activity in older adults with low to moderate physical function.