Faster Kinetics of V̇O₂ During Arm Exercise with Circulatory Occlusion of the Legs

Abstract

Occlusion of the nonworking leg muscles prior to the onset of supine arm exercise was examined for an effect on the kinetics of respiratory gas exchange (V̇O₂ and V̇CO₂), ventilation (V̇_E), and heart rate (HR). Seven subjects performed arm cycling at 40 W (two females) or 50 W (five males) for 8 min following 4 min of “0” W pedaling. Six repetitions of each of uncuffed and cuffed leg conditions were averaged for individual subject analysis. The V̇O₂ kinetics were significantly faster in the cuffed than the uncuffed condition (mean response time 66.0 ± 26.4 vs 81.2 ± 37.5 s, P < 0.04). The kinetics of V̇CO₂, V̇_E, and HR were not affected by occlusion. It is concluded that the faster V̇O₂ kinetics with the prior occlusion of nonworking leg muscles was a consequence of increased availability of oxygen to the working arm muscles at the onset of exercise.

Key words

oxygen uptake - exercise - blood flow distribution - oxygen transport