Intracranial Cerebrovascular Characteristics Associated With Long‐Term Endurance Exercise and Age‐Related Changes: A 4D Flow MRI Study

ABSTRACT Background Cerebrovascular aging is characterized by progressive reductions in cerebral blood flow and vascular compliance. Although long‐term endurance exercise has been associated with improved brain health, its relationship with cerebrovascular aging remains incompletely understood. Purpose To assess associations between long‐term endurance exercise and intracranial arterial structural and hemodynamic characteristics, and to determine whether these associations differ with age. Study Type Prospective cross‐sectional study. Population Fifty‐one endurance runners (≥ 5 h/week endurance exercise for ≥ 3 years) and 51 matched sedentary controls. Field Strength/Sequence Intracranial four‐dimensional velocity‐encoded gradient echo sequence (4D Flow MRI) at 3.0 T. Assessment Luminal cross‐sectional area, blood flow, pulsatility index (PI), and resistive index (RI) were quantified in the bilateral internal carotid arteries and basilar artery. Total cerebral blood flow (TCBF) was calculated from these vessels. Statistical Tests Univariable analysis was used to compare groups. Multivariable linear regression and linear mixed‐effects models were used to assess associations of age and long‐term endurance exercise with cerebrovascular structural and hemodynamic parameters, with additional testing for age‐by‐exercise interactions. A p value < 0.05 was considered significant. Results Endurance runners had significantly higher TCBF than sedentary controls (586.2 ± 85.7 vs. 540.7 ± 85.6 mL/min). Older age was independently associated with lower cerebral blood flow ( β = −2.636 mL/min per year) and higher PI ( β = 0.003 per year), whereas long‐term endurance exercise was independently associated with larger luminal cross‐sectional area ( β = 1.119 mm 2 ) and higher TCBF ( β = 52.929 mL/min) and higher vessel‐level blood flow ( β = 19.313 mL/min). In addition, endurance exercise was associated with higher RI ( β = 0.054) but not PI ( β = 0.026). No significant age‐by‐exercise interactions were observed. Data Conclusion Long‐term endurance exercise was associated with larger intracranial arterial luminal dimensions and higher cerebral blood flow, without significant differences in age‐related hemodynamic changes between groups. Level of Evidence 2. Stage of Technical Efficacy 2.