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

Abstract

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 ($\dot{V}{\text{O}}_{{ 2 {\text{peak}}}}$) 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 $\dot{V}{\text{O}}_{{ 2 {\text{peak}}}}$ [athletes vs controls mean (%) ± SE: −6.9 ± 2.2 vs −5.7 ± 2.3, p = 0.76]. Relative to men with low $\dot{V}{\text{O}}_{{ 2 {\text{peak}}}}$, those with moderate and high $\dot{V}{\text{O}}_{{ 2 {\text{peak}}}}$ had lower age-adjusted AIx@75 (p < 0.001). In women, those with high $\dot{V}{\text{O}}_{{ 2 {\text{peak}}}}$ had lower AIx@75 than those with low and moderate $\dot{V}{\text{O}}_{{ 2 {\text{peak}}}}$ (p < 0.01).

Conclusions

The lower AIx@75 in endurance athletes is partly mediated by $\dot{V}{\text{O}}_{{ 2 {\text{peak}}}}$. While an inverse relationship between AIx@75 and $\dot{V}{\text{O}}_{{ 2 {\text{peak}}}}$ was found in men, women with the highest $\dot{V}{\text{O}}_{{ 2 {\text{peak}}}}$ possessed lowest AIx@75 compared to females with moderate or poor cardiorespiratory fitness. We recommend aerobic training aimed at achieving a minimum $\dot{V}{\text{O}}_{{ 2 {\text{peak}}}}$ of 45 ml kg⁻¹ min⁻¹ to decrease the risk of future cardiovascular events and all-cause mortality.