The impact of exercise training on the diameter dilator response to forearm ischaemia in healthy men

Aim: Recent studies found differences between groups in the rate of diameter increase following the flow-mediated dilation (FMD). Whilst exercise training alters the magnitude of the FMD, little is known about the impact of exercise training on the rate of diameter increase. The aim of this study is to examine post-cuff deflation changes in brachial artery diameter following 5 min forearm ischaemia every 2 weeks across 8-weeks of a handgrip exercise training regimen. Methods: Post-deflation changes in brachial artery diameter following 5-min of ischaemia were examined before, after and every 2-weeks across an8-week handgrip training programme in healthy young men (n = 11) using echo-Doppler. Results: The magnitude of dilation increased at week 2-4-6, but returned towards baseline values at week 8 (anova: P = 0.001). The time-to-peak diameter (42 +/- 15 s) demonstrated a significant prolongation at week 4 (77 +/- 32 s), but returned towards baseline values at weeks 6 and 8 (anova: P < 0.001). The rate of diameter increase did not differ across the intervention. Conclusion: Exercise training in healthy subjects is initially characterized by a larger dilation. Since the rate of dilation did not change, a longer time-to-peak dilation was necessary to achieve the increase in magnitude of dilation. As exercise training continues, the timing and magnitude of the peak diameter response returns to near baseline levels.