Impaired left ventricular systolic function after a half-ironman race

OBJECTIVE: To assess the effects of prolonged strenuous exercise in the for m of a half-ironman (HI) race (2 km swim, 90 km bike ride and a 21 km run) on left ventricular systolic function. METHODS AND RESULTS: The study participants consisted of nine male triathle tes (mean age +/- SD 32 +/-5 years) who competed in the Great White North H I race. Two-dimensional transthoracic echocardiograms were obtained two to three days before the HI (prerace), immediately after completion of the HI (postrace) and 24 h after cessation of exercise. Compared with before the r ace, performing an HI was associated with a decline in systolic blood press ure (prerace 127.2 +/- 15.0 mmHg compared with after the race 116.1 +/- 10. 2 mmHg, P <0.05), the systolic blood pressure to end-systolic cavity area r atio (a surrogate fur left ventricular contractility - prerace 14.3 +/-3.0 mmHg/cm(2) compared with postrace 11.0 +/-2.2 mmHg/cm(2), p <0.05) and the frac tional area change (prerace 54.1 +/-3.8% compared with postrace 47.4 /-5.5%, P <0.05). There was also a concomitant increase in heart rate (prer ace 56.3 +/-9.4 beats/min compared with postrace 74.1 +/- 10.7 beats/min. P <0.05), the end-systolic cavity area (prerace 9.2 +/-2.2 cm(2) compared wi th postrace 10.8 +/-1.9 cm(2), P <0.05) and the end-systolic cavity area to end-systolic myocardial area ratio, prerace 0.39 +/-0.08 compared with pos trace 0.51 +/-0.1, P <0.05), which returned toward baseline values 24 h aft er cessation of the HI. CONCLUSIONS: Performing an HI appears to he associated with a transient imp airment in left ventricular contractility and a subsequent decline in left ventricular systolic function that tends to return toward normal values wit hin 24 h after cessation of exercise.