[Left ventricular function and cardiovascular adaptation to exercise in young sportsmen].
In order to find out whether the expression "sports heart" can be used in children and if so, to give an objective definition of it, we studied a group of 40 young people (mean age 12.2 +/- 1.6 years) subjected to intensive training and practising sports regularly, i.e. about 12 hours of physical activity per weeks on average. The sports practised were mainly tennis among boys and ice-skating among girls. A group of 40 subjects with similar characteristics but no particular physical training was studied simultaneously and served as control. These 80 young people had normal heart structure. All underwent routine cardiovascular examinations (physical, radiological, electrocardiographic), complete one - and two - dimensional echocardiography to evaluate left ventricular function and an exercise-test on ergometric bicycle. No difference was found between the left ventricle of sportsmen and that of controls; in particular, there was neither dilatation nor parietal thickening in sportsmen, so that all functional values were the same. During exercise-tests sportsmen performed better than controls, with significantly longer duration of effort and greater maximal oxygen consumption. However, heart rate at rest, then during exercise and recovery, and variations in systolic blood pressure during exercise and in the 10 minutes which followed were identical in both groups. The only notable difference was a deeper fall in diastolic blood pressure in sportsmen, indicating a better opening of the peripheral vascular bed during exercise. It is concluded that there are few cardiovascular differences between trained sporting children and children with normal physical activity, probably because the relatively short training undergone does not leave sufficient time for most of the adaptation systems to become established.