During incremental upright leg cycling to exhaustion, vasoconstrictor signals efficiently opposed metabolic vasodilatory stimuli in the arms, limiting arm blood flow to 1.2 L/min at maximal exercise.
Observational (n=9)
No
How does incremental upright leg cycling exercise affect central and peripheral hemodynamics and regional blood flow in physically active men?
During upright whole-body exercise, blood flow is differentially regulated in the upper and lower extremities, with vasoconstrictor signals efficiently opposing vasodilatory metabolites in the arms.
Absolute Event Rate: 1.2% vs 0.8%
p-value: p=<0.05
To determine central and peripheral hemodynamic responses to upright leg cycling exercise, nine physically active men underwent measurements of arterial blood pressure and gases, as well as femoral and subclavian vein blood flows and gases during incremental exercise to exhaustion (Wmax). Cardiac output (CO) and leg blood flow (BF) increased in parallel with exercise intensity. In contrast, arm BF remained at 0.8 l/min during submaximal exercise, increasing to 1.2 +/- 0.2 l/min at maximal exercise (P < 0.05) when arm O(2) extraction reached 73 +/- 3%. The leg received a greater percentage of the CO with exercise intensity, reaching a value close to 70% at 64% of Wmax, which was maintained until exhaustion. The percentage of CO perfusing the trunk decreased with exercise intensity to 21% at Wmax, i.e., to approximately 5.5 l/min. For a given local Vo(2), leg vascular conductance (VC) was five- to sixfold higher than arm VC, despite marked hemoglobin deoxygenation in the subclavian vein. At peak exercise, arm VC was not significantly different than at rest. Leg Vo(2) represented approximately 84% of the whole body Vo(2) at intensities ranging from 38 to 100% of Wmax. Arm Vo(2) contributed between 7 and 10% to the whole body Vo(2). From 20 to 100% of Wmax, the trunk Vo(2) (including the gluteus muscles) represented between 14 and 15% of the whole body Vo(2). In summary, vasoconstrictor signals efficiently oppose the vasodilatory metabolites in the arms, suggesting that during whole body exercise in the upright position blood flow is differentially regulated in the upper and lower extremities.
Calbet et al. (Fri,) conducted a observational in Healthy (n=9). Incremental upright leg cycling exercise to exhaustion vs. Submaximal exercise was evaluated on Arm blood flow at maximal exercise (p=<0.05). During incremental upright leg cycling to exhaustion, vasoconstrictor signals efficiently opposed metabolic vasodilatory stimuli in the arms, limiting arm blood flow to 1.2 L/min at maximal exercise.