Augmentation Index and Systolic Load Are Lower in Competitive Endurance Athletes

Background Arterial stiffness increases with age, and chronic endurance exercise has been shown to attenuate increases in arterial stiffness in older individuals. The aim of this study was to assess the effect of varying fitness levels on wave reflection in young healthy adults. Methods A total of 32 subjects (16 competitive endurance athletes and 16 recreationally active subjects) underwent brachial artery blood pressure (BP) measurement (by sphygmomanometry) and central aortic pressure (by noninvasive radial artery applanation tonometry and use of a generalized transfer function) measurements at rest. Central aortic augmentation index (AI), an index of wave reflection, and tension-time index (TTI), an indicator of systolic load, were calculated from the aortic pressure waveform. Physical fitness was determined through a maximal oxygen consumption (VO2max) test performed on a treadmill. Results The two groups did not differ in age, height, weight, resting BP, or blood lipids. The VO2max was significantly higher in the competitive group compared with the recreational group (65 ± 1.9 v 49 ± 1.8 mL/kg/min, P< .05). The AI was lower in the competitive group compared with the recreational group (−2.1% ± 2.1% v 4.5% ± 2.9%, P< .05), as was TTI (1679 ± 61 v 1868 ± 58, P< .05). Conclusions Wave reflection is lower in competitive endurance athletes who have higher fitness levels and who exercise at a higher intensity, for a longer duration, and more frequently as compared with recreationally active individuals. These differences may be due to functional changes that occur as a result of training.