Long-Term Clinical Consequences of Intense, Uninterrupted Endurance Training in Olympic Athletes

Abstract

The aim of this study was to assess incidence of cardiac events and/or left ventricular (LV) dysfunction in athletes exposed to strenuous and uninterrupted training for extended periods of time. Whether highly intensive and uninterrupted athletic conditioning over a long period of time might be responsible for cardiac events and/or LV dysfunction is unresolved. We assessed clinical profile and cardiac dimensions and function in 114 Olympic athletes (78% male; mean age 22 +/- 4 years), free of cardiovascular disease, participating in endurance disciplines, who experienced particularly intensive and uninterrupted training for 2 to 5 consecutive Olympic Games (total, 344 Olympic events), over a 4- to 17-year-period (mean 8.6 +/- 3 years). Over the extended period of training and competition, no cardiac events or new diagnoses of cardiomyopathies occurred in the 114 Olympic athletes. Global LV systolic function was unchanged (ejection fraction: 62 +/- 5% to 63 +/- 5%; p = NS), and wall motion abnormalities were absent. In addition, LV volumes (142 +/- 26 ml to 144 +/- 25 ml; p = 0.52) and LV mass index (109 +/- 21 g/m(2) to 110 +/- 22 g/m(2); p = 0.74) were unchanged, and LV filling patterns remained within normal limits, although left atrial dimension showed a mild increase (37.8 +/- 3.7 mm to 38.9 +/- 3.2 mm; p < 0.001). In young Olympic athletes, extreme and uninterrupted endurance training over long periods of time (up to 17 years) was not associated with deterioration in LV function, significant changes in LV morphology, or occurrence of cardiovascular symptoms or events.