Fitness on White Matter and Cognition in Aging

Cardiorespiratory fitness (CRF) is associated with decreased risk for mild cognitive impairment (MCI) and dementia. CRF is linked with more conserved gray and white matter (WM) volume, improved WM microstructural integrity, and better cognitive performance among healthy older adults. Additional research is needed to determine: (1) which WM tracts are most strongly related to CRF, (2) whether CRF-related benefits on WM translate to enhanced cognitive functioning, and (3) factors that mediate and moderate CRF effects. Higher CRF was hypothesized to be associated with stronger WM integrity, both globally and locally in WM tracts that connect frontal brain regions. The neuroprotective effects were hypothesized to be age-dependent, such that the association between CRF and WM integrity would be stronger in old age compared to younger age. Finally, higher CRF was hypothesized to predict stronger performance on tests of executive functioning (EF), partially mediated by frontal WM integrity. Delineation of specific neurocognitive effects of CRF may serve clinicians in individually tailoring wellness interventions to meet patients' specific cognitive concerns with aging.