Exercise training enhances endothelial function in young men

OBJECTIVES The present study was designed to assess whether exercise traini ng can enhance endothelium-dependent dilatation in healthy young men. BACKGROUND Exercise has been shown to reduce cardiovascular morbidity and m ortality, but the mechanisms for this benefit are unclear. Endothelial dysf unction is an early event in atherogenesis, and animal studies have shown t hat exercise training can enhance endothelial function. METHODS We have examined the effect of a standardized, 10-week, aerobic and anaerobic exercise training program on arterial physiology in 25 healthy m ale military recruits, aged 17 to 24 (mean 20) years, of average fitness le vels. Each subject was studied before starting, and after completing the ex ercise program. Baseline vascular reactivity was compared with that of 20 m atched civilian controls. At each visit, the diameter of the right brachial artery was measured at rest, during reactive hyperemia (increased flow cau sing endothelium-dependent dilation) and after sublingual glyceryltrinitrat e (GTN; an endothelium-independent dilator), using high-resolution external vascular ultrasound. RESULTS At baseline, flow-mediated dilatation (FMD) and GTN-mediated dilata tion were similar in the exercise and control groups (FMD 2.2 +/- 2.4% and 2.4 +/-: 2.8%, respectively, p = 0.33; GTN 13.4 +/- 6.2 vs. 16.7 +/- 5.9, r espectively, p = 0.53). In the military recruits, FMD improved from 2.2 +/- 2.4% to 3.9 +/- 2.5% (p = 0.01), with no change in the GTN-mediated dilati on (13.4 +/- 6.2% vs. 13.9 +/- 5.8%, p = 0.31) following the exercise progr am. CONCLUSION Exercise training enhances endothelium-dependent dilation in you ng men of average fitness. This may contribute to the benefit of regular ex ercise in preventing cardiovascular disease. (C) 1999 by the American Colle ge of Cardiology.