Cardiac Size And Function In School Athletes At Rest And After Exercise

To determine the effect of high school athletics on cardiac structure and function, we performed 2-D directed M-Mode echos on students involved in isometric (IM) and isotonic (IT) sports and compared them to non-athletic controls (C). Measurements were made at rest and immediately after stage 4 treadmill exercise. Twenty students were included in each group. LV mass was greater in both in and IT compared to C (C 111±4, IM 132±3, IT 130±4 g/M2, p<0.05>. In IT LV diastole volume (LVDV) was increased with normal wall thickness/radius ration (t/r), whereas, in IM, LVDV was normal but, t/r was increased. Stroke index (SI) was increased in IT (C 44±1.7, IM 46±1.6, IT 52.3±2.0 ml/M2, p<0.02). Cardiac index (CI) and shortening fractions were similar among the three groups. After exercise LVDV and systolic volume decreased in both C and IT but, remained unchanged in IM. CI increased with exercise in all groups. Although resting systolic (S), diastolic (D), and mean (M), blood pressures (BP) were similar in all groups, after exercise both C and IT had an increase in SBP, (C 39%, IT 32%) and a fall in DBP, (C-26%), IT-27%) HBP remained unchanged. In IM, SBP rose less, 22%, and DBP fell less, −18%. These data suggest that students engaged in ordinary school sports can develop either eccentric or concentric LVH depending upon the type of sport. The IM athlete appears to have a thicker, less compliant LV and demonstrates less change in blood pressure with exercise.