Left ventricular response to exercise in regular runners and controls. A radionuclide evaluation.

Radionuclide angiography was performed during upright exercise to compare left ventricular function in nine regular runners to nine age-matched, healthy controls. Heart rate, blood pressure, left ventricular ejection fraction (LVEF), end diastolic volume index (EDVI), end systolic volume index (ESVI), and stroke volume index (SVI) were measured at rest and at 40%, 60%, 80%, and 100% of maximum work capacity (mean maximal workload [KPM +/- SD] was 1,773 +/- 157 in runners and 1,260 +/- 324 in controls). The resting data of runners and controls were similar. There were no significant differences in heart rate, systolic blood pressure, and LVEF between runners and controls during exercise. SVI and EDVI were higher in runners during exercise (P less than 0.05). ESVI was lower in controls at a 60% level of exercise (P less than 0.05). The data indicate that an early and sustained increase in the diastolic volume of the left ventricle is important for enhanced cardiac performance of regular runners during exercise.