Cardiorespiratory fitness in relation to cerebral vascular and metabolic health in older adults with coronary artery disease

This study investigated whether higher cardiorespiratory fitness (VO₂peak) is associated with better cerebral vascular and metabolic health-specifically cerebral blood flow (CBF), cerebrovascular reactivity (CVR), cerebral metabolic rate of oxygen (CMRO₂), and oxygen extraction fraction (OEF) across healthy older adults and patients with coronary artery disease (CAD). Thirty-seven healthy adults (65.3 ± 8.3 years old) and 35 CAD patients (66.4 ± 9.3 years old) underwent calibrated fMRI using hypercapnic and hyperoxic gas challenges (including carbogen) to quantify gray matter CBF, CVR, CMRO₂, and OEF. VO₂peak was obtained from a maximal cycle ergometer cardiopulmonary exercise test. Associations between VO₂peak and brain biomarkers were evaluated with group terms to test CAD-specific effects. Across all participants, VO₂peak was positively associated with CBF (β = 0.32, p = 0.02) and CVR (β = 0.002, p = 0.04) in gray matter, indicating an association between aerobic fitness and vascular health. Metabolic effects differed by group: in CAD patients, VO₂peak correlated positively with CMRO₂ (β = 0.08, p = 0.02), suggesting higher fitness may be associated with preserved oxidative metabolism, while in healthy controls, VO₂peak was negatively associated with OEF (β = -3.6, p = 0.02), consistent with aging-related adaptations driven by improved CBF without CMRO₂ changes. VO₂peak is positively associated with cerebral vascular function in older adults and shows group-specific metabolic benefits: in CAD, higher VO₂peak relates to preserved CMRO₂, whereas in healthy individuals it is linked primarily to enhanced perfusion and reduced extraction. These findings support aerobic exercise as a promising strategy to mitigate CAD-related brain alterations and highlight VO₂peak as a potentially modifiable target for prevention and rehabilitation.