Effect of three different protocols of aerobic interval exercise over fat oxidation

Abstract

Objectives: The objective of this research is to explore the influence of different exercise protocols on fat oxidation. Design: Uncontrolled experimental study. Methods: For this purpose, 10 sedentary male subjects were recruited, 30 to 39 years old, with elevated body mass index (BMI). Each participant was evaluated in four separate sessions. The first session consisted in determining peak aerobic power (PAP). The following sessions participants performed three equivalent exercise protocols, consisting of each one in three bouts of 15-minute exercise separated by 5 minutes of rest in between. The constant intensity protocol included exercise periods at 55% of PAP, while the other two (increasing and decreasing intensity protocols) consisted in exercise periods at 40, 55 and 70% of PAP in an increasing or decreasing order respectively. Results: There were no significant differences (P > 0.05) in total caloric expenditure among the three protocols (range: 5.9 ± 0.2 to 6.1 ± 0.2 kcal·kg−1). DIP causes a progressive increase in fat oxidation comparative to IIP and CIP protocols (P < 0.01). In period third of the protocols, DIP oxidized significantly more fat than the other two. The perception of effort was significantly lower in the DIP compared to the other two protocols (P < 0.01). Conclusions: Fat oxidation in exercises at intervals of different intensity depends on the order of these periods, being greater when performed decreasingly, as well as the perception of effort, being more useful for sedentary subjects with high BMI.