Effect of regular exercise on coronary endothelial function in patients with recent myocardial infarction. 
Exercise training improves the endothelial function of arteries in skeletal muscle, but few studies have examined its clinical effect on human coronary endothelial function.  Non-infarct-related coronary arteries in 41 patients with a recent myocardial infarction who underwent successful percutaneous transluminal coronary angioplasty were studied.  Patients were divided into 2 groups: regular exercisers (n=24, 17 males, mean age: 58 years), and non-exercisers (n=17, 12 males, mean age: 58 years).  Acetylcholine (ACh) was infused into the non-infarct-related coronary artery and its diameter was measured by quantitative angiography at baseline and at 6 months after angioplasty.  ACh, given in doses of 1, 3, 10, 30 microg/min, increased the coronary artery diameter in a dose-dependent manner in both groups.  The mean percent change in the diameter at the site of stenosis change (%DS) was less in the regular exercisers than in the non-exercisers (11%+/-12 vs 41%+/-36, p<0.05).  Multivariate analysis showed that regular exercise was the only significant determinant of improvement in endothelial function (p=0.01).  These findings suggest that regular exercise improves endothelial function in the coronary arteries following myocardial infarction.