Six Weeks of Forearm Training Improves Resting Brachial Arterial Function

Abstract

PURPOSE: To determine if a) forearm blood flow (FBF) and vascular conductance (VC) increase more in exercise-trained forearms during dynamic handgrip exercise, and b) the sympatholytic response of the trained forearm is enhanced during handgrip exercise performed with a strong sympathetic stimulus. METHODS: Six men participated in the 6-week longitudinal training regimen. Training consisted of 4 sets of handgrip exercise of the nondominant forearm at 70% MVC using a cycle of 1.5 s contracted:1.5 s relaxed for 1.5 min, 3 d.wk-1. Brachial arterial blood flow (Doppler ultrasound), blood pressure, heart rate and VC were measured at rest, during a cold pressor test (CPT), during dynamic submaximal handgrip exercise at 30% MVC with and without a CPT, and during reactive hyperemia. RESULTS: Forearm volume and maximal voluntary contraction both increased significantly (P < 0.05) in the nondominant forearm after training. After training, absolute FBF, relative FBF, and VC were higher (P < 0.05) at rest. Mean arterial pressure (MAP) was significantly higher (P < 0.05) during reactive hyperemia after training but there were no differences in FBF or VC. Training had no effect on FBF, VC, or MAP during steady state handgrip exercise, with or without a CPT. CONCLUSIONS: These findings suggest that although exercise training may enhance vascular function at rest, the sympatholytic response of the trained forearm during exercise with a strong sympathetic stimulus is not altered.