Sex Differences in Ventricular-Vascular Interactions Associated with Aerobic Capacity

Abstract

Background: Aerobic capacity as measured by peak oxygen uptake (VO2peak), is related to functional capacity and is a strong independent predictor of all-cause and disease-specific mortality. Lifelong exercise is associated with reduced central arterial and ventricular stiffness, potential mechanisms that may underpin cardiovascular health benefits as a result of endurance training. The purpose of this study was to evaluate sex-specific ventricular-vascular interactions associated with VO2peak in healthy males and females. Methods: Sixty-eight males and females (35 10 years) characterized as recreational exercisers to highly trained endurance athletes, and free of chronic disease underwent a cycle ergometer test to exhaustion to assess aerobic capacity (VO2peak). Resting arterial compliance and echocardiographic evaluation of left ventricular (LV) function were measured. Results: VO2peak was similar between groups (54 6 vs. 50 7). LV mass indexed to body surface area (LVMI) was higher (110 20 vs. 94 18, p=0.001) and longitudinal diastolic strain rate was lower (1.6 0.3 vs. 1.4 0.2, p=0.005) in males. Linear regression analysis revealed LVMI and longitudinal diastolic strain rate were significantly associated with VO2peak (r2=0.32, p=0.001) in males, while in females LVMI and large artery compliance were the key factors influencing VO2peak (r2=0.61, p<0.001). Conclusion: These findings reveal that in females much of the variance in VO2peak can be attributed to ventricular and vascular adaptations, whereas in males, cardiac factors of structure and function accounted for the majority of this variance. The substantive central vascular adaptations to exercise observed in females in this study further validates engagement in endurance training to prevent age-related arterial stiffening in women.