The effect of high-intensity interval training and moderate-intensity continuous training on aerobic fitness and body composition in males with overweight or obesity: A randomized trial

The optimal exercise training characteristics for improving body composition in individuals with obesity are not clear. This study assessed the effects of 6-weeks of high-intensity interval training (HIIT) or moderate-intensity continuous training (MICT) on aerobic fitness and body composition in males with overweight or obesity. Twenty-eight participants (18–45 years; BMI: 25–35 kg/m2) performed stationary cycling 3 times per week for 6 weeks. Participants were randomly allocated to work-matched HIIT (N = 16) (10 × 1-min intervals at ~90% peak heart rate) or MICT (N = 12) (30 min at 65–75% peak heart rate). Maximal aerobic capacity (VO2peak) and body composition were assessed before and after 6-week training. Both HIIT and MICT induced moderate increases in aerobic fitness (Δ% VO2peak: HIIT 9 ± 8%, ES = 0.42; MICT: 7 ± 13%, ES = 0.32) and work capacity (Δ% peak workload: HIIT 13 ± 10%, ES = 0.69: MICT 17 ± 15%, ES = 0.76), but these changes did not differ significantly between the groups (all p > 0.16). The effects of HIIT or MICT on body composition outcomes were negligible to small across whole-body and all regional-specific sites (all effect sizes ES = −0.19 to 0.38) and did not differ significantly between the groups (all p > 0.21). Short-term (6-weeks) cycling training did not improve body composition in males with overweight or obesity. Improvements in aerobic fitness were comparable between work-matched HIIT and MICT.