Effect of extreme exercise on myocardial function as assessed by tissue Doppler imaging.

Background: Response of the human heart to exercise has been studied extensively, but little information is available on the effects of exhaustive exercise on cardiac performance.

Objectives: The aim of this study was to evaluate the effect of severe prolong exercise on both left and right ventricular performance. To maximize the sensitivity of our study we used tissue Doppler imaging.

Methods: Participants in army ranger training program were invited to participate in this prospective study. All patients underwent transthoracic echocardiography using tissue Doppler imaging before and after Ranger training program.

Results: A total of 45 consecutive male rangers who completed 8 weeks of training were included in this study. Peak systolic myocardial velocity (S) decreased significantly after training (12.46 +/- 0.54 vs. 9.93 +/- 0.45 cm/s; P < 0.001). In the right ventricle, tissue Doppler measures of systolic and early diastolic function decreased significantly after training compared to pretraining values.

Conclusion: In conclusion, very strenuous prolonged exercise may result in depressed left ventricular contractile function. This raises the possibility of cardiac fatigue.