Substrate utilization during and after high intensity exercise in healthy lean and obese men

Abstract

Objective: To compare lipid and carbohydrate use during and after a high-intensity endurance exercise bout between lean and obese subjects. Material and Method: Lean and obese healthy male subjects with energetic physical activity and stable body weight were recruited to participate in the present study. The respiratory exchange ratio (RER), lipid and carbohydrate oxidation, and lipid and carbohydrate energy expenditure during resting condition, high-intensity exercise and 180 min after exercise were determined by indirect calorimetry. Results: Ten lean and ten obese healthy male subjects, aged 26+4 years, completed a 300-kcal high-intensity exercise session. Resting energy expenditure and lipid energy expenditure in the obese group were significantly higher than those of the lean group. The RER, lipid oxidation, and carbohydrate oxidation were not significantly different between groups throughout the exercise period. The total energy expenditure and total lipid and carbohydrate energy expenditure were also not significantly different between lean and obese groups. During the 180-minute post exercise period, both lean and obese subjects showed a declination in RER and carbohydrate oxidation and an increase in lipid oxidation. Conclusion: Substrate use during and after high-intensity exercise between healthy lean and obese subjects was not significantly different. Both groups used carbohydrates and lipids as the main substrate sources during and after high-intensity exercise, respectively.