Left Ventricular Dimensions Following Training in Young and Middle-Aged Men

Abstract

To document the effects of endurance training upon left ventricular dimensions, an echocardiographic examination was performed on 11 young (19 ± 1 years) and 13 middle-aged (40 ± 3 years) subjects before and after a 20-week endurance training program, The maximal working capacity was increased by 28% and 27% in young and in middle-aged subjects, respectively. Following training, the left ventricular posterior wall and septal thickness in diastole were unchanged both in young (10.1 ± 0,2 mm and 9.0 ± 0.2 mm, pre-; 10.1 ± 0.2 mm and 9.3 ± 0.3 mm, post-) and in middle-aged subjects (10.0 ± 0.3 mm and 10.2 ± 0.3 mm, pre-; 9.7 ± 0.2 mm and 10.1 ± 0.2 mm, post-); the left ventricular end-diastolic internal diameter was unchanged in middle-aged subjects (47.8 ± 0.9 mm, pre-; 48.1 ± 1.0 mm, post-) but was significantly increased in young subjects (47.8 ± 1.0 mm, pre-; 49.9 ± 1.0 mm, post-) u°<0.05). These data could suggest that the left ventricular adaptation to training decreases with age. However, the decrease in resting heart rate observed in young subjects (68 ± 3 to 60 + 2 beats·min^-1) (P < 0.05) but not in middle-aged subjects (63 ± 3 and 65 ± 3 beats·min^-1) could also increase diastolic filling time and explain the small left ventricular end-diastolic enlargement found in the young subjects.

Key words

echocardiography - left ventricle - endurance - resting bradycardia - age