مطهره محبی نژاد

The aim of this study is to compare the effect of high intensity interval training (HIIT) and moderate intensity continuous training (MICT) on body composition in adults with overweight and obese.

A systematic search of English and Persian articles published in PubMed, Web of Science, SID, and Magiran databases was conducted up to November 2022. A meta-analysis was performed to compare the effect of HIIT and MICT on body composition in adults with overweight and obese. Weighted mean difference (WMD) and 95% confidence interval (CI) were calculated using fixed effect model.  Also, I2 test was used to determine heterogeneity, and Funnel plot test and Egger test were used for publication bias.

The results of 36 studies with 1096 subjects showed that HIIT did not significantly change in body weight [WMD = 0.37, (-1.12 to 0.24), P = 0.3], body fat percentage [WMD = 0.31 (-0.19 to 0.83), P = 0.2], and body fat mass [WMD = -0.43 (-1.12 to 0.24), P = 0.2], compared to MICT in adults with overweight and obese. But HIIT causes a significant increase in body free fat mass [WMD = 0.82 (0.07 to 1.58), P = 0.03], compared to MICT in adults with overweight and obese.

The results of the present study show that HIIT has similar benefits to MICT on body composition, and body fat reduction, although HIIT is a time-efficient training method.  However, neither of the short-term HIIT nor MICT results in a clinically significant reduction in body fat. HIIT leads to an increase in body free fat mass in obese adults compared to MICT.