Exercise training improves left ventricular systolic function in older men

Abstract

To determine whether endurance exercise training can improve left ventricular systolic function in older men, 10 healthy sedentary men (64 ± 3 years old; mean ± SD) were studied. Training consisted of endurance exercise 4 ± 0.3 days per week for 11.8 ± 2.5 months at a progressively increasing intensity of 60-80% of maximal O2 uptake (Vo2max) with additional brief bouts of exercise equal to 93 ± 13% of Vo2max. Vo2max increased from 29.6 ± 4.1 to 37.2 ± 5.7 ml/kg/min (p<0.001). Percent body fat was decreased (17.8 ± 3.6% versus 15.6 ± 3.6%; p<0.001). Before training, left ventricular ejection fraction, determined by electrocardiographic-gated equilibrium blood pool imaging, increased only modestly during exercise (from 66.3 ± 6.7% at rest to 70.6 ± 6.9% at peak exercise). After training, the increase in ejection fraction during exercise was significantly greater (from 67 ± 4.8% at rest to 77.6 ± 7.5% at peak exercise) than that observed before training and was similar to that in young sedentary men (64 ± 7% at rest versus 74 ± 9% at peak exercise). Although the changes in systolic pressure from rest to exercise were similar, end-systolic volume decreased significantly at peak exercise after (51 ± 12 versus 38 ± 13 ml; p<0.005) but not before (46 ± 8 versus 43 ± 13 ml; p=NS) training with a shift in the end-systolic volume-systolic blood pressure relation to the left compatible with enhanced inotropic state. Exercise training induced proportional increases in left ventricular end-diastolic diameter and posterior wall thickness, measured echocardiographically, with no change in the wall thickness-to-radius ratio (0.27 ± 0.04 versus 0.28 ± 0.03), suggestive of volume-overload hypertrophy. End-diastolic volume at rest was increased (138 ± 11 versus 155 ± 26 ml; p<0.05). Stroke volume was significantly greater at peak exercise in response to training (110 ± 17 ml before versus 132 ± 27 ml after training; p<0.05). The differences in end-diastolic volume and stroke volume at peak exercise between the trained and untrained states correlated strongly (r=0.95). At a given increase in end-diastolic volume during exercise, the increase in stroke volume was more after than before training. Furthermore, at a given change in end-systolic volume from rest to exercise, the subjects attained a higher systolic blood pressure after than before training. These data suggest that endurance exercise training of sufficient intensity can improve left ventricular systolic performance in older men.