ENHANCED VASODILATION TO ACETYLCHOLINE IN ATHLETES IS ASSOCIATED WITHLOWER PLASMA-CHOLESTEROL

We investigated a change in vascular reactivity as a potential adaptiv e mechanism to chronic exercise. The study consisted of 2 separate pro tocols with 10 male athletes and 10 age-matched sedentary male control subjects participating in each. Protocol 1 investigated forearm blood flow responses to intra-arterial infusions of acetylcholine and sodiu m nitroprusside by use of venous occlusion plethysmography. Protocol 2 used identical techniques to study responses to norepinephrine, angio tensin II (ANG II), and N-G-monomethyl-L-arginine (L-NMMA). The percen t reduction in forearm vascular resistance to acetylcholine was signif icantly greater in the athletic compared with the sedentary group (mul tivariate analysis of variance for repeated measures, P = 0.03), Covar iance analysis suggested that the lower total cholesterol level of the athletic group (P = 0.03) may contribute to their enhanced responsive ness to acetylcholine. There were no differences between athletic and sedentary groups in the forearm vascular resistance responses to norep inephrine, ANG II, sodium nitroprusside, or L-NMMA. These data support the hypothesis that long-term endurance training is associated with e nhanced endothelium-dependent dilator reserve due to altered lipoprote in levels in athletes. This finding may have therapeutic application i n conditions of elevated cholesterol and impaired vasodilator capacity including hypertension, hypercholesterolemia, atherosclerosis, and ca rdiac failure.