Indices of leg resistance artery function are independently related to cycling V̇O₂ max

While maximum blood flow influences one's maximum rate of oxygen consumption (V̇O₂ max), with so many indices of vascular function, it is still unclear if vascular function is related to V̇O₂ max in healthy, young adults. The purpose of this study was to determine if several common vascular tests of conduit artery and resistance artery function provide similar information about vascular function and the relationship between vascular function and V̇O₂ max.

Twenty-two healthy adults completed multiple assessments of leg vascular function, including flow-mediated dilation (FMD), reactive hyperemia (RH), passive leg movement (PLM), and rapid onset vasodilation (ROV). V̇O₂ max was assessed with a graded exercise test on a cycle ergometer.

Indices associated with resistance artery function (e.g., peak flow during RH, PLM, and ROV) were generally related to each other (r = 0.47-77, p < .05), while indices derived from FMD were unrelated to other tests (p < .05). Absolute V̇O₂ max (r = 0.57-0.73, p < .05) and mass-specific V̇O₂ max (r = 0.41-0.46, p < .05) were related to indices of resistance artery function, even when controlling for factors like body mass and sex. FMD was only related to mass-specific V̇O₂ max after statistically controlling for baseline artery diameter (r = 0.44, p < .05).

Indices of leg resistance artery function (e.g., peak flow during RH, PLM, and ROV) relate well to each other and account for ~30% of the variance in V̇O₂ max not accounted for by other factors, like body mass and sex. Vascular interventions should focus on improving indices of resistance artery function, not conduit artery function, when seeking to improve exercise capacity.