Abstract
The purpose of this study was to determine the effects of aerobic exercise on endothelium-dependent vasodilation in humans. We evaluated the forearm blood flow (FBF) response to acetylcoline (ACh), an endothelium-dependent vasodilator, and isosorbide dinitrate (ISDN), an endothelium-independent vasodilator, before and after exercise (bicycle ergometers, 30 min, 5 to 7 times per week, for 12 weeks, 50%Vo2max) in healty young men (n=8, mean age: 27 ± 3 yr). FBF was measured using a mercury-filled Silastic strain-gauge plethysmograpy. Twelve weeks of exercise significantly augmentated ACh-induced vasodilation (7.5 ± 2.4 to 11.4 ± 5.8 ml/min/100 ml tissue, p<0.05). Aerobic exercise didn't alter ISDN-induced vasodilation. Administration of NG-monomethyl-L-arginin (L-NMMA), a nitric oxide synthase inhibitor, abolished exercise-induced augmentation of the FBF response to ACh. These findings suggest that aerobic exercise augments endothelium-dependent vasodilation in humans through the increased nitric oxide production.
