Exercise Mode Moderates the Relationship Between Mobility and Basal Ganglia Volume in Healthy Older Adults

OBJECTIVES: To examine whether 12 months of aerobic training (AT) moderated the relationship between change in mobility and change in basal ganglia volume than balance and toning (BAT) exercises in older adults. DESIGN: Secondary analysis of a randomized controlled trial. SETTING: Champaign-Urbana, Illinois. PARTICIPANTS: Community-dwelling older adults (N = 101; mean age 66.4). INTERVENTION: Twelve-month exercise trial with two groups: AT and BAT. MEASUREMENTS: Mobility was assessed using the Timed Up and Go test. Basal ganglia (putamen, caudate nucleus, pallidum) was segmented from T1-weighted magnetic resonance images using the Oxford Centre for Functional Magnetic Resonance Imaging of the Brain Software Library Integrated Registration and Segmentation Tool. Measurements were obtained at baseline and trial completion. Hierarchical multiple regression was conducted to examine whether exercise mode moderates the relationship between change in mobility and change in basal ganglia volume over 12 months. Age, sex, and education were included as covariates. RESULTS: Exercise significantly moderated the relationship between change in mobility and change in left putamen volume. Specifically, for the AT group, volume of the left putamen did not change, regardless of change in mobility. Similarly, in the BAT group, those who improved their mobility most over 12 months had no change in left putamen volume, although left putamen volume of those who declined in mobility levels decreased significantly. CONCLUSION: The primary finding that older adults who engaged in 12 months of BAT training and improved mobility exhibited maintenance of brain volume in an important region responsible for motor control provides compelling evidence that such exercises can contribute to the promotion of functional independence and healthy aging.