[Effect of adaptation to physical loads on the contractile function and mass of the left ventricle of the heart].

Echocardiography was used to examine 20 highly trained athletes and 12 untrained persons at rest and during increasing physical load. It was established that in untrained persons the stroke volume in moderate and large physical loads increases mainly due to an increase in the diastolic output with the systolic output unchanged. In highly trained athletes the stroke volume with an equal load increases due both to growth in the diastolic output and to considerable decrease in the systolic output, i.e., due to the more complete ejection of blood from the cavity of the ventricle. As a result in trained patients a sufficient minute output in physical exertion is attained with less external work of the left ventricle and myocardial tension.