Better cardiovascular fitness is associated with better structural brain integrity in midlife: A population‐representative birth cohort study

Abstract

AbstractBackgroundImproving cardiovascular fitness has been promoted as a promising nonpharmacological strategy for buffering against age‐related cognitive decline and mitigating risk for Alzheimer’s disease and related dementia (ADRD). These beneficial effects may be related to the capacity for improved cardiovascular fitness to stave off age‐related brain atrophy. However, there is evidence that some neurological benefits associated with adult cardiovascular fitness may be better explained by early childhood factors—referred to as neuroselection—rather than any active neuroprotective effects of fitness on the brain.MethodData from 875 participants from the population‐representative Dunedin Study were utilized to investigate associations between cardiovascular fitness (VO2Max) at age 45, changes in cardiovascular fitness across adulthood, and structural brain integrity (cortical thickness, surface area, and subcortical grey matter volume) at age 45. Critically, the potential confounding effects of childhood IQ on any observed associations in midlife were evaluated in order to disentangle potential neuroselective from neuroprotective effects.ResultBetter VO2Max at age 45 was associated with thicker cortex in frontal and temporal lobes (βs:0.14 to 0.25, Figure 1b) and smaller hippocampal fissure volumes at age 45 (β=‐0.18). Higher rates of decline in VO2max were associated with lower total (β=‐0.11) and distributed regional (βs:‐0.11 to ‐0.19, Figure 2b) surface area at age 45. These associations were unaffected by the inclusion of childhood IQ in the analyses.ConclusionBetter midlife cardiovascular fitness may offer neuroprotective effects on brain structure, which may in turn mitigate ADRD risk and buffer against cognitive decline.