Effects of HIIT-based training protocols on body composition and physical fitness in overweight and obese adults: a systematic review

Abstract

Overweight and obesity are associated with adverse health consequences and unfavorable cardiometabolic outcomes. The objective of this systematic review was to evaluate the effects of different high-intensity interval training (HIIT) protocols on body composition and physical fitness in overweight and obese people. Relevant literature published from 2020 to 2026 was systematically retrieved from the Web of Science, PubMed, and Scopus databases. Eight studies satisfied the inclusion criteria. The results showed that HIIT-based therapies consistently had a positive effect on both body composition and physical fitness. Reductions in body weight, body fat percentage, fat mass, body mass index (BMI), visceral fat, and blood pressure, as well as gains in muscle mass, fat-free mass (FFM), aerobic fitness, maximal oxygen uptake (VO₂max), peak oxygen uptake (VO₂peak), and fat oxidation, were common findings. All methods studied were effective: aquatic HIIT, hybrid HIIT, resistance training mixed with HIIT, running-based HIIT, and low-frequency HIIT. In conclusion, HIIT seems to be an effective and time-efficient intervention for increasing body composition and cardiorespiratory fitness in people with overweight and obesity. However, exercise recommendations should be customized.