Aerobic Capacity Independently Predicts Central Augmentation Index Among Apparently Healthy Adults

Central augmentation index, a reflection of both arterial stiffness and ventricular-vascular coupling, is influenced by age and body height. High aerobic capacity and lower total body fat percentage are cardioprotective, but their combined influence on central augmentation index is not entirely clear. PURPOSE: To determine the extent to which cardiorespiratory fitness and total body fat percentage influence central augmentation index, a measure of arterial wave reflection and stiffness, in apparently healthy adults. METHODS: Community dwelling adults between ages 24 and 79 years were screened to exclude clinical and occult cardiovascular disease. Arterial wave reflection was measured noninvasively as central augmentation index (AIx). Aerobic capacity was assessed as maximal oxygen uptake (VO2max) during an incremental treadmill exercise test. Body composition was determined using a dual -energy X-ray absorptiometry and % total body fat was used for analyses. RESULTS: Across the cohort (age: 43.5 ± 12.1 years; 53 men; 42 women), significant Pearson correlations were observed between AIx and age (r = 0.47, p < 0.001), height (r = -0.32, p = 0.002), % total body fat (r = 0.29, p = 0.004) and VO2max (r = -0.52, p < 0.001). Multiple linear regression with backwards selection was conducted and VO2max (β = -0.54), age (β = 0.24), and height (β = -0.60) were found to be significant predictors of AIx (p < 0.05), accounting for 37% of the variance. Total % body fat was not a significant predictor of AIx (p = 0.90). CONCLUSIONS: In an apparently healthy adult population, AIx was strongly influenced by aerobic fitness, after accounting for confounding factors, including age and height. In contrast, % total body found did not influence AIx.