Not Just for Joints: The Associations of Moderate-to-Vigorous Physical Activity and Sedentary Behavior with Brain Cortical Thickness

Introduction Cortical thinning is associated with aging; however, lifestyle factors can moderate this relationship. Two distinct lifestyle behaviors associated with brain health are regular moderate-to-vigorous physical activity (MVPA) and limited sedentary behavior (SB). However, it is unclear whether MVPA and SB levels contribute to cortical thickness independent of each other. We therefore investigated the independent relationships of MVPA and SB with cortical thickness using baseline data from a randomized controlled trial. Methods At baseline, we measured MVPA and SB for 7 d using the SenseWear Mini. A subset of the randomized controlled trial participants (n= 30) underwent a 3T magnetic resonance imaging scan, wherein region-specific cortical surface morphometric analyses were performed using T1-weighted structural magnetic resonance imaging. We conducted regression analyses using a surface-based cluster size exclusion method for multiple comparisons within FreeSurfer neuroimaging software to determine if MVPA and SB are independently correlated with region-specific cortical thickness. Results This subset of participants had a mean age of 61 yr (SD = 9 yr), and 80% were female. Higher MVPA was associated with greater cortical thickness in the temporal pole (cluster size, 855 mm(2); cortical thickness range, 2.59-3.72 mm(2);P< 0.05) and superior frontal gyrus (cluster size, 1204 mm(2); cortical thickness range, 2.41-3.15 mm(2);P< 0.05) of the left hemisphere, independent of SB. Sedentary behavior was not associated with greater cortical thickness in any region, independent of MVPA. Conclusions Our results indicate that adults with greater MVPA-independent of SB-are associated with greater cortical thickness in regions, which are susceptible to age-associated atrophy.