PsyArXiv · Oct 21, 2026
The Association Between Cardiorespiratory Fitness and White Matter Integrity Across the Lifespan: A Systematic Review
By de Oliveira RM, Lox C
White matter deterioration is a hallmark of cognitive aging and a core feature of manyneurodegenerative disorders. Cardiorespiratory fitness (CRF) has emerged as a modifiable factorthat may support white matter integrity across the adult lifespan. This systematic review, using anarrative synthesis, examined findings from 24 studies, identified through a systematic search ofPubMed, Web of Science, and PsycINFO databases, examining the association betweenobjectively measured CRF and neuroimaging-based white matter structure. Results revealed aconsistent positive relationship between higher CRF and stronger microstructural integrity,particularly in late-myelinating tracts such as the corpus callosum, cingulum, and longitudinalfasciculi. These associations were minimal in young adulthood, mixed in midlife, and mostrobust in adults over 60, suggesting an age-dependent neuroprotective effect that strengthensacross the lifespan. Higher CRF was also linked to reduced white matter hyperintensity (WMH)burden in older populations. While cross-sectional evidence for this relationship was largelyconsistent, findings from randomized controlled trials were considerably more mixed, with mostintervention studies failing to detect group-level improvements in white matter microstructuredespite confirmed fitness gains. These findings underscore the potential of CRF as a nonpharmacological strategy to preserve brain health and mitigate cognitive decline with age. Futureresearch should adopt longitudinal and multimodal designs to clarify causal mechanisms andidentify age-specific moderators of these effects. Keywords: cardiorespiratory fitness, white matter, fractional anisotropy, aging, aerobic exercise