Assessment of the Effects of Aerobic Fitness on Cerebrovascular Function in Young Adults Using Multiple Inversion Time Arterial Spin Labeling MRI.

Catherine Foster,Valentina Tomassini,Richard G Wise,Daniel Helme,Jessica J Steventon

doi:10.3389/fphys.2020.00360

Catherine Foster, Valentina Tomassini + Show 3 more

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https://doi.org/10.3389/fphys.2020.00360

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Abstract

This cross-sectional study investigated the effects of aerobic fitness on cerebrovascular function in the healthy brain. Gray matter cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) were quantified in a sample of young adults within a normal fitness range. Based on existing Transcranial Doppler ultrasound and fMRI evidence, we predicted a positive relationship between fitness and resting gray matter CBF and CVR. Exploratory hypotheses that higher O2peak would be associated with higher GM volume and cognitive performance were also investigated. 20 adults underwent a O2peak test and a battery of cognitive tests. All subjects also underwent an MRI scan where multiple inversion time (MTI) pulsed arterial spin labeling (PASL) was used to quantify resting CBF and CVR to 5% CO2. Region of interest analysis showed a non-significant inverse correlation between whole-brain gray matter CBF and O2peak; r = −0.4, p = 0.08, corrected p (p′) = 0.16 and a significant positive correlation between O2peak and whole-brain averaged gray matter CVR; r = 0.62, p = 0.003, p′ = 0.006. Voxel-wise analysis revealed a significant inverse association between O2peak and resting CBF in the left and right thalamus, brainstem, right lateral occipital cortex, left intra-calcarine cortex and cerebellum. The results of this study suggest that aerobic fitness is associated with lower baseline CBF and greater CVR in young adults.

Highlights

The study was approved by the Cardiff University School of Psychology Research Ethics Committee and performed in accordance with the guidelines stated in the Cardiff University Research Framework
Informed written consent was obtained from all subjects
Answering this question will guide optimal exercise dose recommendations and interventional studies

Summary

Introduction

Aerobic fitness has emerged as a modifiable lifestyle factor which reduces the risk of all-cause mortality (Kodama et al, 2009; Lee et al, 2010), cardiovascular events (Haskell et al, 2007; Lee et al, 2010; Roque et al, 2013) and protects the brain against age and disease-related decline (Hillman et al, 2008; Hayes et al, 2014a; Nishijima et al, 2016). Neuroimaging studies have provided evidence of a neuroprotective effect of aerobic fitness in older adults, linking higher aerobic fitness with greater brain volume (Erickson et al, 2011) and cerebral blood flow (CBF) (Thomas et al, 2013). Gauthier et al (2015) found that in older adults, BOLD CVR was negatively correlated with V O2max in frontal regions but positively correlated in periventricular white matter and portions of the somatosensory cortex. These conflicting CVR data represent an issue of inconsistent findings regarding aerobic fitness and its effects on cerebrovascular function across the lifespan

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