RESUMEN
<p><b>OBJECTIVE</b>To explore the new indexes and new methods for the noninvasive measuring and evaluating cardiac function detection of the athletes.</p><p><b>METHODS</b>Heart sound signals were sampled randomly from 81 students in physical education department (experiment group) and 41 students in general departments (control group) after completing designed workload during step-climbing exercise, the contrast study on heart rate, D/S ratio as well as the S1/S2 ratio of students from physical education and general department has been conducted.</p><p><b>RESULTS</b>In the resting state, the physical education department students' heart rate and D/S ratio was 66 +/- 8.7 and 2.04 +/- 0.33 respectively; general department students' heart rate and D/S ratio was 71 +/- 8.0 and 1.82 +/- 0.27 respectively. In the whole exercise, the physical education department students S1/S2 ratio was 7.34 +/- 4.04; general department students S1/S2 ratio was 5.22 +/- 2.38.</p><p><b>CONCLUSION</b>Students from physical education department have higher level of cardiac reserve than that of students from general department. The method can evaluate cardiac reserve for athletes and general persons, and provide a new quantity evaluation index for selecting athletes and evaluating cardiac function of general persons.</p>