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

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

JOURNAL=Frontiers in Physiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2020.00360

DOI=10.3389/fphys.2020.00360

ISSN=1664-042X

ABSTRACT=<p>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 <inline-formula><mml:math id="INEQ1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mi>V</mml:mi><mml:mo>.</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub>peak would be associated with higher GM volume and cognitive performance were also investigated. 20 adults underwent a <inline-formula><mml:math id="INEQ2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mi>V</mml:mi><mml:mo>.</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub>peak 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% CO<sub>2</sub>. Region of interest analysis showed a non-significant inverse correlation between whole-brain gray matter CBF and <inline-formula><mml:math id="INEQ3" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mi>V</mml:mi><mml:mo>.</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub>peak; <italic>r</italic> = −0.4, <italic>p</italic> = 0.08, corrected <italic>p</italic> (<italic>p</italic>′) = 0.16 and a significant positive correlation between <inline-formula><mml:math id="INEQ4" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mi>V</mml:mi><mml:mo>.</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub>peak and whole-brain averaged gray matter CVR; <italic>r</italic> = 0.62, <italic>p</italic> = 0.003, <italic>p</italic>′ = 0.006. Voxel-wise analysis revealed a significant inverse association between <inline-formula><mml:math id="INEQ5" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mover accent="true"><mml:mi>V</mml:mi><mml:mo>.</mml:mo></mml:mover></mml:math></inline-formula>O<sub>2</sub>peak 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.</p>