Abstract

To assess left ventricular structure and function at rest and during exercise in endurance athletes, 10 elite marathon runners, aged 28 to 37 years, and 10 matched nonathletes were studied by echocardiopraphy and supine bicycle ergometry. Each athletes best marathon time was <2 h 16 min. Echocardiography war performed at rest, at a 60 W work load and at an individually adjusted work load, at which heart rate was 110 beats/min (physical working capacity 110 (PWC110)). Oxygen uptake at PWC110 averaged (+-SD) 1.14 +- 0.2. liters/min in the nonathletes and 2.0+- 0.2 liters/min in the runners. The left ventricular internal diameter at end-diastole was imilar at the three activity levels in the control subjects but increased significantly from rest to exercise in the runners. Left ventricular systolic meridional wall stress remained unchange during exercise in the nonathletes but was significantly higher at PWC110 in the athletes. Both the systolic peak velocity of posterior wall endocardial displacement and fractional shortening of the left ventricular internal diameter increased with exercise; at PWC110 the endocardial peak velocity was higher in the runners than in the control subjects. The endocardial peak velocity during relaxation was comparable in athletes and control subjects at rest, increased similarly at a 60 W work load, but was higher in the runners at PWC110. In conclusion, left centricular dynamics during supine bicycle exercise between elite marathon runners and nonathletes; centricular dilation, with preserved fractional shortening, and a faster relaxation may contribute of the development of a high stroke volume in the exercising athlete. Verf.-Referat