Assessment of the effects of aerobic fitness on cerebrovascular function in young adults using multiple inversion time arterial spin labelling MRI

Abstract

The cross-sectional study investigated the effects of aerobic fitness on cerebrovascular function in the healthy brain. We quantified grey matter (GM) cerebral blood flow (CBF) and cerebrovascular reactivity (CVR), in a sample of young adults within a normal fitness range. Based on existing TCD and fMRI evidence, we predicted a positive relationship between fitness and resting GM CBF, and CVR. Exploratory hypotheses that higher [Formula] peak would be associated with higher GM volume and cognitive performance were also investigated. 20 adults underwent a [Formula] peak test and a battery of cognitive tests. All subjects underwent an MRI scan where multiple inversion time (MTI) pulsed arterial spin labelling (PASL) was used to quantify resting CBF and CVR to 5% CO2. ROI analysis showed a non-significant negative correlation between whole-brain GM CBF and [Formula] peak; r=-0.4, p=0.08, corrected p (p) =0.16 and a significant positive correlation between [Formula] peak and voxelwise whole-brain GM CVR; r=0.62, p=0.003, p =0.006. Voxelwise analysis revealed a significant inverse association between [Formula] peak and resting CBF in the left and right thalamus, brainstem, right lateral occipital cortex, left intracalcarine cortex and cerebellum. The results of this study suggest that aerobic fitness is associated with lower CBF and greater CVR in young adults.