Influence of Insulin Resistance on the Balance between Carbohydrate and Fat Utilization at Rest and in progressive Intensity Exercise

Purpose::Analyze the influence of insulin resistance on the balance between carbohydrate and fat utilization at rest and in progressive intensity exercise. Methods:Twelve sedentary male subjects were divided into two groups (>RI and < RI) according with their insulin resistance index (HOMA-IR). Using indirect calorimetry were analyzed: carbohydrate and fat utilization at rest, the crossover point, the exercise intensity that elicits a maximal fat oxidation (Fatmax), carbohydrate and fat utilization at Fatmax. All variables were compared using the MANNWHITNEY test. Results:There were no significant differences between the group in Fatmax (37,35±7,99 vs. 39,81±3,84%VO2 max) and the Crossover point (40,08±7,19 vs. 40,67±5,12%VO2 máx). Also had not been observed any significant difference in the substrate balance at rest (0,095±0,009 vs. 0,069±0,028 g/min, 0,244±0,082 vs. 0,250±0,073 g/ min, fat and carbohydrate, respectively) and at Fatmax (0,397±0,087 vs. 0,230±0,076 g/min, 0,689±0,229 vs. 0,867±0,222 g/min, fat and carbohydrate, respectively). Conclusions:Insulin resistance did not influence the Crossover point and the Fatmax, as well as the substrate balance at rest and at Fatmax.