Effects of intensive physical conditioning on cardiovascular parameters of high-level athletes

Summary

The potential effect of short-duration intensive training on cardiac function was investigated in 18 endurance athletes, 9 marathon runners and 9 cross-country skiers. Electrovectorcardiogram, M-mode echocardiogram, maximal exercise testing and a 24-h Holter ECG were performed before and at the end of a 3-month span of intensive training. Among the cardiac parameters studied, the only statistically significant changes were, in skiers: prolongation of PR interval, increase in QRS duration, decrease in left maximal spatial voltage, increase in physical capacity and, in runners: increase in left posterior wall thickness over left ventricular (LV) diastolic diameter. However, most indices of left ventricular mass and function already exceeded the upper limits of normal at the first examination, especially in runners. The absence of clinically significant modification after intensive training indicates that these parameters reflect structural changes which cannot be further modified by short-term conditioning.