Increased insulin resistance decreases exercise tolerance in patients with hypertension and/or dyslipidemia

Abstract

Background: It is considered that increased insulin resistance is closely correlated with the exercise capacity in patients with hypertension (HT) and/or dyslipidemia (DL), because it is known to impair the energy metabolism in skeletal muscles. The aim of this study was to investigate the influence of insulin resistance on the exercise capacity in patients with HT and/or DL. Methods: We recruited 45 patients with HT and/or DL and assessed their homeostasis model assessment ratio (HOMA-R)as a parameter of insulin resistance. Patients were defined to have insulin resistance, if their HOMA-R showed >2.50. Patients were divided into low and high HOMA-R groups based on 2.50 of HOMA-R. Oxygen uptake (VO2) at anaerobic threshold (VO2 AT) and peak VO2 were measured by cardiopulmonary exercise testing (CPX) using a treadmill. The exercise capacity was assessed using ratios of measured VO2 to predicted VO2 AT and predicted peak VO2 (%VO2 AT and %peak VO2, respectively). The number of steps per day was counted for 2 weeks as a parameter of physical activity. We compared %VO2 AT, %peak VO2 and physical activity between the two groups and determined correlations of %VO2 AT and %peak VO2 with HOMA-R using a single regression analysis. Results: There were no significant differences in clinical characteristics and physical activity between the two groups. The %VO2 AT and %peak VO2 were 93% and 90% in the low HOMA-R group and 76% and 72% in the high HOMA-R group, respectively. They were significantly lower in the high HOMA-R group than in the low HOMA-R group (P<0.05, respectively), and negatively correlated with HOMA-R (r=0.339, P<0.05 and r=0.522,P<0.001, respectively) (Figure). ![Figure][1] Conclusion: The present study showed that increased insulin resistance decreased exercise capacity in patients with HT and/or DL. [1]: pending:yes