High intensity interval training increases the utilization of fatty acids in subjects with overweight or obesity. A randomized study

Abstract

Introduction: the effect of high intensity interval training (HIIT) on fat utilization during exercise needs to be studied in depth. Objective: to determine the effect of HIIT training program in subjects with overweight or obesity on the use of fat during exercise, body composition and cardiovascular variables. The second objective was to compare the variables according to the duration of the program (i.e., 12, 16 and 20 weeks). Material and methods: 30 subjects were studied (age 44.8 ± 11.6 years). Three groups were formed at random, the G1 (12 weeks, n = 12, 48.08 ± 8.20 years), G2 (16 weeks, n = 10, 42.10 ± 11.60 years) and G3 (20 weeks, n = 8, 43.38 ± 15.76 years). All groups performed HIIT 3 times per week. Results: the three groups showed a significant decrease in body fat percentage (p < 0.05), without differences between groups. Similarly, cardiovascular variables did not report differences between groups (p-interaction > 0.05) after the intervention; however, the groups reported a significant decrease systolic blood pressure (p < 0, 05). In the pre vs. post analysis by groups, the three groups showed improvements in VO2max without differences between groups (p-interaction > 0.05). Finally, the three groups increased the fats utilization during exercise (p < 0.05). Conclusion: the program increased fat utilization during exercise, decreased body fat % and improved cardiovascular parameters, however after 12 training weeks it is advisable to apply variations to training to maximize results.