Myocardial adaptation and efficiency in response to intensive physical training in elite speedskaters.

BACKGROUND: Physiological cardiac adaptations to exercise training resulting in the 'athlete's heart' are well known. Most of these studies, however, were included either those who exercise to exhaustion, non-elite athletes or those who participate primarily in sports requiring extensive weight training. Studies utilizing conventional and tissue Doppler echocardiographic studies in highly competitive elite athletes whose training includes both aerobic and weight training are limited.

AIMS AND METHODS: 1) To identify baseline cardiovascular structural and physiologic adaptations present in elite athletes who participate in both endurance aerobic and weight training programs and to compare them to similarly aged sedentary controls. The population includes 24 speedskaters participating in the 2006 Olympic Games and 15 sedentary young subjects. 2) To evaluate possible structural and physiologic cardiac changes following short duration, vigorous exercise. We repeated the baseline echocardiographic protocol in the athletes following a 3000 m sprint conducted at race pace.

RESULTS: Compared to non-athletes, the atrial and left ventricular (LV) volumes at rest were larger in elite athletes. There was enhanced LV diastolic function as manifested by higher early annular (septal and lateral) tissue Doppler velocities (E'): 12.7+/-2.3 vs 11.3+/-1.1 cm/s and 17.4+/-4.7 vs 14.4+/-1.2 cm/s, P=0.025 and 0.020 respectively. Evidence of right ventricular (RV) remodeling included larger basal RV dimensions (38+/-5 vs 32+/-4 mm, P=0.001), attenuated RV systolic function at rest (RV area change 35+/-13% in athletes vs 47+/-11% in controls, P=0.006) and lower RV systolic strain rate (SSR) 1.9+/-0.5 vs 2.9+/-1.1/s, P<0.001). However, there was better right ventricular (RV) diastolic function at rest, E': 13.5+/-3.6 vs 11.1+/-1.5 cm/s (P=0.016). Following exercise, the athletes exhibited augmentation of RV systolic function with increased RV fractional area change (increasing to 43+/-10%, P=0.007) and SSR (2.5+/-1.2/s post-exercise, P=0.038).

CONCLUSION: Participation by world-class speedskaters in a vigorous training regimen results in cardiovascular anatomic and physiologic adaptations. These changes, including cardiac chamber dilatation, enhanced ventricular diastolic function and attenuated resting RV systolic function, are likely adaptive and allow for more efficient energy use at rest and a robust response to demands of exercise.