Le chémoréflexe des membres inférieurs élève le débit sanguin et la consommation d'oxygène musculaire au début d'un exercice modéré des membres supérieurs

Abstract

Aim – Test the hypothesis that increases in forearm blood flow (FBF) during the adaptive phase at the onset of moderate exercise would allow a more rapid increase in muscle oxygen uptake (VO 2mus). Materials and methods – Nine subjects completed forearm exercise in control (Ref) and leg occlusion (Occ) conditions. In Occ, exercise of ischemic calf muscles was performed prior to the onset of forearm exercise to activate the muscle chemoreflex evoking a 25 mmHg increase in mean arterial pressure that was sustained during forearm exercise. Results – A higher VO 2mus accompanied the higher FBF during the adaptive phase of the Occ tests, yet there was no difference in the baseline or steady state VO 2mus between Occ and Ref. Supplying more blood flow at the onset of exercise allowed a more rapid increase in oxidative phosphorylation supporting our hypothesis that, at least for this type of exercise, O 2 supply is rate limiting.