Abstract

Background —In sedentary humans endothelium-dependent vasodilation is impaired with advancing age contributing to their increased cardiovascular risk, whereas endurance-trained adults demonstrate lower age-related risk. We determined the influence of regular aerobic exercise on the age-related decline in endothelium-dependent vasodilation. Methods and Results —In a cross-sectional study, 68 healthy men 22 to 35 or 50 to 76 years of age who were either sedentary or endurance exercise–trained were studied. Forearm blood flow (FBF) responses to intra-arterial infusions of acetylcholine and sodium nitroprusside were measured by strain-gauge plethysmography. Among the sedentary men, the maximum FBF response to acetylcholine was 25% lower in the middle aged and older compared with the young group ( P <0.01). In contrast, there was no age-related difference in the vasodilatory response to acetylcholine among the endurance-trained men. FBF at the highest acetylcholine dose was almost identical in the middle aged and older (17.3±1.3 mL/100 mL tissue per minute) and young (17.7±1.4 mL/100 mL tissue per minute) endurance-trained groups. There were no differences in the FBF responses to sodium nitroprusside among the sedentary and endurance- trained groups. In an exercise intervention study, 13 previously sedentary middle aged and older healthy men completed a 3-month, home-based aerobic exercise intervention (primarily walking). After the exercise intervention, acetylcholine-mediated vasodilation increased ≈30% ( P <0.01) to levels similar to those in young adults and middle aged and older endurance-trained men. Conclusions —Our results indicate that regular aerobic exercise can prevent the age-associated loss in endothelium-dependent vasodilation and restore levels in previously sedentary middle aged and older healthy men. This may represent an important mechanism by which regular aerobic exercise lowers the risk of cardiovascular disease in this population.