Effects of high-intensity interval training (HIIT) and maximum fat oxidation intensity training (MFOIT) on body composition, inflammation in overweight and obese adults

Background. - The purpose was to compare the effects of a 12 -week HIIT and MFOIT on body composition and the levels of IL -1 (3 , IL -6, and IL -10 in overweight and obese adults. Methods. - Fifty-three physically inactive adults (19 males and 34 females) were randomly assigned: a control group (CON, n = 17), an HIIT group ( n = 17) performing 4 x 3 minutes of exercise at 80% VO2max interspersed with 50% VO2max (weeks 1-4) and 90% VO2max interspersed with 60% VO2max (weeks 5-12), and MFOIT ( n = 19) performing 40 minutes (weeks 1-4), 50 minutes (weeks 5-8), and 60 minutes (weeks 9-12) of exercise at the intensity that maximizes fat oxidation. Body fat percentage, muscle mass, fat mass, and the levels of IL -1 (3 , IL -6, and IL -10 were assessed at baseline and after the 12 -week training period. Results. - (1) The indices of body composition followed a normal distribution and were analyzed using analysis of variance. Both MFOIT and HIIT showed significant time effects on body weight, body fat percentage, and fat mass. (2) The immune indices did not follow a normal distribution, therefore, non -parametric tests were used. No significant intergroup effects were found on the immune indices across all groups, although IL -6 levels were significantly increased after MFOIT. IL -1 B levels were significantly higher after both MFOIT and HIIT. Conclusion. - This study demonstrates that both HIIT and MFOIT are effective in reducing body fat and body fat percentage, thus improving body composition. Additionally, MFOIT significantly increased IL -6 concentration compared to HIIT, potentially due to differences in exercise duration. Chinese Clinical Trial Registry number. - ChiCTR1900022315 (registration date: 4 April 2019). (c) 2024 Elsevier Masson SAS. All rights reserved.