Impact of acute dynamic exercise and arterial shear rate modification on radial artery low-flow mediated constriction in young men

Abstract

Purpose Leg cycling exercise acutely augments radial artery low-flow mediated constriction (L-FMC). Herein, we sought to determine whether this is associated with exercise-induced changes in arterial shear rate (SR). Methods Ten healthy and recreationally active young men (23 ± 2 years) participated in 30 min of incremental leg cycling exercise (50, 100, 150 Watts). Trials were repeated with (Exercise + WC) and without (Exercise) the use of a wrist cuff (75 mmHg) placed distal to the radial artery to increase local retrograde SR while reducing mean and anterograde SR. Radial artery characteristics were measured throughout the trial, and L-FMC and flow mediated dilatation (FMD) were assessed before and acutely (~ 10 min) after leg cycling. Results Exercise increased radial artery mean and anterograde SR, along with radial artery diameter, velocity, blood flow and conductance (P  0.05) but also increased retrograde SR (P  0.05). In contrast, no change in FMD was observed in either Exercise or Exercise + WC trials (P > 0.05). Conclusions These findings indicate that increases in L-FMC following exercise are abolished by the prevention of increases radial artery diameter, mean and anterograde SR, and by elevation of retrograde SR, during exercise in young men