The Relationship Between Cardiorespiratory Fitness and Aortic Stiffness in Women with Central Obesity

Abstract

Purpose: To examine the association between cardiorespiratory fitness and aortic stiffness in women with central obesity. The secondary purpose was to examine whether traditional and nontraditional cardiovascular risk factors mediate the relationship between cardiorespiratory fitness and aortic stiffness. Materials and Methods: Eighty-seven centrally obese women (age, 42 +/- 9 years, [body mass index (BMI)] 28 +/- 3 kg/m(2)) participated in this cross-sectional study. Central obesity was defined as a waist circumference >85 cm. Pulse wave velocity (PWV) was obtained from the carotid and femoral pulse sites using applanation tonometry to measure aortic stiffness. Maximal aerobic capacity (VO2 Max) was estimated using a submaximal walk test and taken as a measure of cardiorespiratory fitness. Potential correlates of both cardiorespiratory fitness and aortic stiffness examined in this study included the following: triglycerides (TG), C-reactive protein (CRP), homeostasis model assessment of insulin resistance index (HOMA-IR), and pulsatile load (i.e., heart rate x aortic pulse pressure [aPP]). Results: Pearson's bivariate correlations indicated that estimated VO2 Max was inversely associated with PWV (r=-0.330, p < 0.05). Using hierarchical multiple regression, the association between estimated VO2 Max and PWV was no longer significant after controlling for traditional and nontraditional cardiovascular risk factors, age, BMI, TG, CRP, HOMA-IR, and pulsatile load (beta = 0.121, p > 0.05). Conclusion: In centrally obese women, cardiorespiratory fitness was inversely associated with aortic stiffness. Associations were not independent of traditional and nontraditional cardiovascular disease (CVD) risk factors. This suggests that higher levels of cardiorespiratory fitness may indirectly reduce aortic stiffness through its beneficial effects on traditional and nontraditional CVD risk factors in women with central obesity.