Effects of aerobic exercise intervention on the association between brain functional connectivity and cognition among older adults

Abstract

Chronic aerobic exercise is known to protect against brain and cognitive aging in animals, but it remains unclear whether these benefits are consistent across the span of older adulthood. Using time-varying effect modeling (TVEM) analysis, this study investigated how the associations between changes in cognition and brain network functional connectivity (FC), induced by a 6-month aerobic exercise intervention, vary with age among older adults aged 55 to 80 (n = 107). Participants were divided into two groups based on exercise intensity: moderate-to-vigorous (ModVig group) and light-intensity (Light group). Before and after the intervention, participants completed cognitive tasks measuring executive function (EF) and processing speed (PS) and underwent resting-state fMRI sessions. FC was assessed across large-scale brain networks, including the frontoparietal control (FPCN), default mode (DMN), dorsal attention (DAN), limbic (LN), salience (SN), somatomotor (SMN), and visual network (VN). Change scores for each cognitive task and FC network were calculated by subtracting pre-intervention scores from post-intervention scores. Older adults in the ModVig group demonstrated improved PS performance at ages 58 to 65 and increased FC at ages 67 to 69 in the DAN. When individuals were exposed to ModVig intensity exercise, increases in FC within the FPCN, DMN, and SN were associated with improved EF and PS performance in those in their mid-60s to mid-70s. These findings support the importance of targeting higher moderate-to-vigorous aerobic exercise intensity for interventions, particularly in this age group, to enhance brain and cognitive health.