Daily aerobic exercise improves reactive hyperemia in patients with essential hypertension

The effects of long-term aerobic exercise on endothelial function in patien ts with essential hypertension remain unclear, To determine whether endothe lial function relating to forearm hemodynamics in these patients differs fr om normotensive subjects and whether endothelial function can be modified b y continued physical exercise, we randomized patients with essential hypert ension into a group that engaged in 30 minutes of brisk walking 5 to 7 time s weekly for 12 weeks (n=20) or a group that underwent no activity modifica tions (control group, n=7). Forearm blood flow was measured using strain-ga uge plethysmography during reactive hyperemia to test for endothelium-depen dent vasodilation and after sublingual nitroglycerin administration to test endothelium-independent vasodilation. Forearm blood flow in hypertensive p atients during reactive hyperemia was significantly less than that in normo tensive subjects (n=17). Increases in forearm blood flow after nitroglyceri n were similar between hypertensive and normotensive subjects. Exercise low ered mean blood pressure from 115.7+/-5.3 to 110.2+/-5.1 mmHg (P<0.01) and forearm vascular resistance from 25.6+/-3.2 to 23.2+/-2.8 mm Hg/mL per minu te per 100 mL tissue (P<0.01); no change occurred in controls. Basal forear m blood flow, body weight, and heart rate did not differ with exercise. Aft er 12 weeks of exercise, maximal forearm blood flow response during reactiv e hyperemia increased significantly, from 38.4+/-4.6 to 47.1+/-4.9 mL/min p er 100 mL tissue (P<0.05); this increase was not seen in controls. Changes in forearm blood flow after sublingual nitroglycerin administration were si milar before and after 12 weeks of exercise. Intra-arterial infusion of the nitric oxide synthase inhibitor N-G-monomethyl-L-arginine abolished the en hancement of reactive hyperemia induced by 12 weeks of exercise. These find ings suggest that through increased release of nitric oxide, continued phys ical exercise alleviates impairment of reactive hyperemia in patients with essential hypertension.