The Right Heart of Elite Male and Female Cyclists: A Comparative Study of Cycling Disciplines

Background: Elite cycling can be dichotomised into road (endurance cycling) and track (sprint cycling) events that are associated with different training components and athlete physiology. Evidence of disproportionate right ventricular (RV) remodelling in endurance athletes places importance on defining physiological and athletic phenotypes. Therefore, the elite cyclist serves as an ideal model to study training-specific adaptations in the right heart. Methods: One hundred and eighty-six (110 males and 76 females) elite international-level cyclists (mean age 23 ± 5 years) were grouped by discipline (endurance cycling and sprint cycling) and sex (male cyclists and female cyclists). RV and right atrial (RA) structure and function was assessed with 2D, tissue Doppler, and strain echocardiography. Structural data were scaled allometrically to body size. Group comparisons were made with a two-way ANOVA. Results: Significantly larger absolute and scaled RV and RA structural values were seen in male and endurance cyclists (RV end diastolic area index: male endurance 14 ± 2 cm2/m2, male sprint 13 ± 2 cm2/m2) than female and sprint cyclists (female endurance 13 ± 2 cm2/m2, female sprint 11 ± 2 cm2/m2), respectively. Endurance training exposure was significantly correlated to structural parameters (RA area index: r = 0.53; p < 0.001). Sex and discipline showed significant impact on resting RV function with reduced RV strain values in male and endurance cyclists (RV basal strain: male endurance −17.5 ± 4.0%, male sprint −19.4 ± 4.6%) compared to female and sprint cyclists (female endurance −19.9 ± 3.9%, female sprint −22.1 ± 5.1%), respectively. There were no significant correlations between training exposure and resting RV function. Conclusions: Athlete sex and cycling discipline exert significant effects on RV and RA structure and function in elite cyclists. The strong correlations observed between endurance training exposure and right heart structure emphasise the importance of consideration of sporting discipline in elite athletes.