Supplementary file 1_Effects of high-intensity interval training versus continuous aerobic training on body weight, body mass index, and body fat percentage in youth with overweight or obesity: a systematic review and meta-analysis.docx

Sensitivity, subgroup, and small-study-effect analyses were also performed.</p>Results<p>Fourteen independent randomized trials were included. For body weight, 13 trials involving 409 participants showed no statistically significant difference between HIIT and continuous aerobic training (MD = −0.37 kg, 95% CI −0.89 to 0.15; P = 0.146; I² = 0%). For BMI, 14 trials involving 432 participants also showed no significant difference (MD = −0.14 kg/m², 95% CI −0.31 to 0.02; P = 0.089; I² = 0%).

For body fat percentage, 11 trials involving 331 participants showed no significant difference (MD = −0.33 percentage points, 95% CI −1.33 to 0.67; P = 0.481), with moderate-to-substantial heterogeneity (I² = 60.3%). Sensitivity analyses did not materially alter the findings, and subgroup analyses did not identify reliable effect modification by weekly frequency, intervention duration, or mean age. Egger’s tests did not detect statistically significant small-study effects.

One trial was at low overall risk of bias, whereas 13 raised some concerns.</p>Conclusion<p>Randomized evidence identified through December 31, 2024 does not show that HIIT provides greater reductions in body weight, BMI, or body fat percentage than continuous aerobic training. HIIT may be considered an alternative exercise format, but the limited evidence base and heterogeneity in body fat outcomes warrant cautious interpretation.</p>