LEFT-VENTRICULAR FUNCTION DURING DYNAMIC EXERCISE IN UNTRAINED AND MODERATELY TRAINED SUBJECTS

The influence of exercise training on left ventricular function at res t (R), at anaerobic threshold (AT), and during peak exercise (PE) was evaluated in 12 healthy untrained and 13 trained (T) subjects who unde rwent Doppler echocardiography at R and radionuclide ventriculography at R and during exercise. The end-diastolic volume and stroke volume w ere significantly higher in the T group than in the untrained group at R. The ejection fraction rose significantly from R to AT and from AT to PE (80.0 +/- 0.84 vs. 83.6 +/- 0.91%), but no significant differenc e was observed between groups. The peak diastolic filling rate rose si gnificantly during exercise, with a further significant increase obser ved in the T group (AT, 6.38 +/- 0.40 vs. 5.01 +/- 0.16 end-diastolic counts/s; PE, 8.24 +/- 0.42 vs. 7.15 +/-0.35 end-diastolic counts/s). The percent variation of minimal systolic counts fell significantly at AT and PE in relation to R. Our data demonstrate that exercise traini ng produces a significant increase in peak diastolic filling rate but no change in systolic function during exercise and that metabolic acid osis caused by exercise does not limit systolic function.