Examining the effects of light versus moderate to vigorous physical activity on cognitive function in African American adults

Background: Physical activity (PA) recommendations for older adults often endorse participation in moderate to vigorous intensity (MVPA). However, health disparities are evident such that African Americans engage in lower levels of MVPA, have a higher prevalence of chronic health and cognitive impairments. The purpose of this cross-sectional study was to examine the role of light PA in addition to MVPA and their associations with measures of executive function among African American older adults. Methods: One hundred and ten participants (mean age = 64.78 +/- 5.7, males = 14) completed measures of cognitive functioning, including the Trail making, Flanker and the N-back tasks. Additionally, participants completed a 6-minute walk test to estimate their cardiovascular fitness and were given an Actigraph accelerometer for 7-days to objectively assess their light and MVPA. Results: Regression analyses controlling for age, fitness and education showed that higher levels of light PA but not MVPA predicted better cognitive performance on the incongruent flanker reaction time (beta=-.24), trails B (beta=-.24) and 1-back accuracy (beta=.28). Both light PA and MVPA predicted faster reaction times on the 1-back and 2-back conditions of the n-back (light PA: beta's=-.22-.23; MVPA: beta's=-.28). Conclusions: Light PA demonstrated similar or better associations than MVPA with cognitive functions which are known to decline with age. Designing and promoting light PA interventions in African American older adults maybe more feasible given the prevalence of disability and functional health disparities. Intervention studies testing the efficacy and effectiveness of light PA are needed and could have a significant public health impact among aging African Americans.