Aortic augmentation index in endurance athletes: a role for cardiorespiratory fitness

Purpose: Endurance exercise improves cardiovascular health and reduces mortality risk. Augmentation index (AIx) reflects adverse loading exerted on the heart and large arteries and predicts future cardiovascular disease. The purpose of this study was to establish whether endurance athletes possess lower AIx and aortic blood pressure compared to healthy controls, and to determine the association between AIx and cardiorespiratory fitness. Methods: Forty-six endurance athletes and 43 healthy controls underwent central BP and AIx measurements by non-invasive applanation tonometry before a maximal exercise test. Peak oxygen uptake (VO₂peak) was assessed by pulmonary analysis. Results: Relative to controls, athletes had significantly lower brachial diastolic blood pressure (BP, -4.8 mmHg, p < 0.01), central systolic BP (-3.5 mmHg, p = 0.07), and AIx at a heart rate of 75 beats min-1 (AIx@75, -11.9 %, p < 0.001). No AIx@75 differences were observed between athletes and controls when adjusted for age and VO₂peak [athletes vs controls mean (%) ± SE: -6.9 ± 2.2 vs -5.7 ± 2.3, p = 0.76]. Relative to men with low V02peak, those with moderate and high VO₂peak had lower age-adjusted AIx@75 (p < 0.001). In women, those with high VO₂peak had lower AIx@75 than those with low and moderate VO₂peak (p < 0.01). Conclusions: The lower AIx@75 in endurance athletes is partly mediated by VO₂peak. While an inverse relationship between AIx@75 and VO₂peak was found in men, women with the highest VO₂peak possessed lowest AIx@75 compared to females with moderate or poor cardiorespiratory fitness. We recommend aerobic training aimed at achieving a minimum VO₂peak of 45 ml kg⁻¹ min⁻¹ to decrease the risk of future cardiovascular events and all-cause mortality.