Aortic augmentation index in endurance athletes: a role for cardiorespiratory fitness.
OBJECTIVE
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 ([Formula: see text]) 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 [Formula: see text] [athletes vs controls mean (%) ± SE: -6.9 ± 2.2 vs -5.7 ± 2.3, p = 0.76]. Relative to men with low [Formula: see text], those with moderate and high [Formula: see text] had lower age-adjusted AIx@75 (p < 0.001). In women, those with high [Formula: see text] had lower AIx@75 than those with low and moderate [Formula: see text] (p < 0.01).


CONCLUSIONS
The lower AIx@75 in endurance athletes is partly mediated by [Formula: see text]. While an inverse relationship between AIx@75 and [Formula: see text] was found in men, women with the highest [Formula: see text] possessed lowest AIx@75 compared to females with moderate or poor cardiorespiratory fitness. We recommend aerobic training aimed at achieving a minimum [Formula: see text] of 45 ml kg(-1) min(-1) to decrease the risk of future cardiovascular events and all-cause mortality.
School of Science and Technology, University of New England, Armidale, NSW, 2351, Australia. jdenham2@une.edu.au.|Faculty of Science and Technology, Federation University Australia, University Drive, Mt Helen, VIC, Australia. jdenham2@une.edu.au.
Joshua
http://orcid.org/0000-0001-5804-4960
J
Denham
Faculty of Health, Federation University Australia, University Drive, Mt Helen, VIC, Australia.
Nicholas J
NJ
Brown
Department of Cardiovascular Sciences, University of Leicester, Leicester, UK.
Maciej
M
Tomaszewski
Institute of Cardiovascular Sciences University College London (UCL) and National Institute for Health Research (NIHR) UCL/UCL Hospitals Biomedical Research Centre, London, UK.
Bryan
B
Williams
Faculty of Health, Federation University Australia, University Drive, Mt Helen, VIC, Australia.
Brendan J
BJ
O'Brien
Faculty of Science and Technology, Federation University Australia, University Drive, Mt Helen, VIC, Australia.
Fadi J
FJ
Charchar
D000293:Adolescent; D000328:Adult; D001011:Aorta / Q000502:physiology*; D062186:Arterial Pressure / Q000502:physiology*; D054874:Athletic Performance / Q000502:physiology; D000072599:Cardiorespiratory Fitness / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013177:Sports / Q000502:physiology*; D059289:Vascular Stiffness / Q000502:physiology*; D055815:Young Adult
Arterial stiffness; Cardiovascular health; Central blood pressure; VO2max