[Influence of exercise training on left ventricular performance investigated by two-dimensional echocardiography]

The influence of exercise training on left ventricular performance was investigated by exercise two-dimensional echocardiography in 12 top-ranking Japanese volleyball players and 10 untrained subjects. Left ventricular wall thickness and dimension were greater in the athletes than in the nonathletes. The left ventricular wall thickness-internal radius ratio, however, was nearly the same in both groups. At rest, heart rate, the stroke area index, % fractional area and the cardiac index were significantly lower in the athletes than in the nonathletes. During exercise, heart rate was slower in the athletes at every exercise stress stage. The stroke area index, % fractional area and the cardiac index increased linearly in the athletes, although these indices of the nonathletes reached a plateau at the moderate exercise stage. The double product at the last stage was greater in the athletes than in the nonathletes. Both groups did not differ as to segmental fractional area change of left ventricular contraction at rest and during exercise. Serum norepinephrine concentration was significantly lower in the athletes than in the nonathletes at rest. After exercise, however, the difference between the two groups was not apparent. It is suspected that exercise training increased the exercise capacity due to an increase in the left ventricular systolic function reserve, the increment of cardiac VO2 max, and the change of blood flow distribution, and generalized aerobic metabolism in various organs.