Indices of leg resistance artery function are independently related to cycling V̇O ₂ max

Abstract

Purpose While maximum blood flow influences one's maximum rate of oxygen consumption (V̇O2max), with so many indices of vascular function, it is still unclear if vascular function is related to V̇O2max 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 V̇O2max. Methods 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). V̇O2max was assessed with a graded exercise test on a cycle ergometer. Results 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 V̇O2max (r = 0.57–0.73, p < .05) and mass‐specific V̇O2max (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 V̇O2max after statistically controlling for baseline artery diameter (r = 0.44, p < .05). Conclusion 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 V̇O2max 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.

Fitness Level‐ and Sex-Related Differences in Macrovascular and Microvascular Responses during Reactive Hyperemia

“…On the other hand, the lack of a significant association between V˙O 2max and the %FMD can be justified by the fact that the same percent change in diameter would have a far less pronounced effect on blood flow in a smaller compared with a larger artery. Gifford and colleagues (39) recently reported similar findings, showing no relationship between V˙O 2max and %FMD but significant correlations between V˙O 2max and indices of resistance artery function. These findings and our findings are in contrast with those from a meta-analysis by Montero (40), who suggested that %FMD is related to V˙O 2max .…”

From heart to muscle: pathophysiological mechanisms underlying long-term physical sequelae from SARS-CoV-2 infection

“…Overall, inflammation, oxidative stress, and autonomic dysfunction can, independently or concurrently, modulate vasomotor tone and contribute to peripheral vascular dysfunction post-COVID-19. Given the link between lower limb vasodilatory capacity and V̇ o 2peak ( 59 , 60 ), this vascular dysfunction is also likely to compromise O 2 delivery to the exercising muscle, leading to reduced exercise tolerance and physical function following COVID-19 infection. It will be important to determine whether this vascular dysfunction is transient or if it increases future risk of cardiovascular disease.…”

Impact of Interrepetition Rest on Muscle Blood Flow and Exercise Tolerance during Resistance Exercise

“…Previous studies demonstrated greater reactive hyperemia among physically active individuals than sedentary individuals [24,25]. With a sample size of 10 subjects from a variety of training backgrounds, it is unknown how well these results apply to the broader population or specific patient populations.…”

“…The leg was rested at 90 • of knee flexion to minimize the impact that differing degrees of knee flexion have on the blood flow response to knee extension exercise [23]. Since the hyperemic response to knee extension is influenced by the amount of external work performed during a contraction [24,25], the displacement distance of the weight was limited to 15 cm for each contraction. Limiting the displacement distance to 15 cm also prevented the subjects from fully extending and "locking out" their knees, which could introduce undesired bouts of rest between concentric and eccentric contractions.…”

“…As mentioned, resistance exercise is associated with high intramuscular pressures that impinge upon the skeletal muscle vasculature, increasing vascular resistance and decreasing blood flow in the process [10,12]. Blood flow increases abruptly between contractions in a process known as "reactive hyperemia", which is when intramuscular pressures decrease [18,19,24,25].…”