The Effects of High-Intensity Interval Training on Inflammatory Cytokines in Children and Adolescents with Obesity: A Systematic Review and Meta-Analysis

TL;DR

This study finds that high-intensity interval training can lower C-reactive protein levels in children and adolescents with obesity, but has no significant effect on other inflammatory markers.

Contribution

The study provides new evidence on the effectiveness of HIT in reducing CRP in children with obesity and identifies key moderators of the intervention effects.

Findings

HIT significantly reduced C-reactive protein levels in children with obesity.

Intervention duration, work-and-rest ratio, and work time were significant moderators of HIT effectiveness.

No significant effects were observed for interleukin 6 and tumor necrosis factor-alpha.

Abstract

Background: High-intensity interval training (HIT) is a time-efficient strategy to improve metabolic health in children, but its impact on inflammatory markers is still unclear. Therefore, we conducted a meta-analysis to examine the role of HIT on pro-inflammatory cytokines including C-reactive protein (CRP), interleukin 6 (IL-6), and tumor necrosis factor-alpha (TNF-α) in children with overweight/obesity. Methods: A meta-analysis was conducted following PRISMA guidelines. PubMed, Web of Science, Scopus, and Embase were searched up to 31 July 2025, for studies involving children with overweight/obesity aged 6 to 18 years. Randomized controlled trials and non-randomized controlled trials with outcome measurements that included CRP, IL-6, and TNF-α were included. Random-effects models were used to aggregate a mean effect size (ES) with 95% confidence intervals (CI), and potential moderators were explored. Results: In total, 768 participants from 15 studies were included. HIT significantly improved CRP (574 participants, 13 studies, SMD = −0.63, 95% CI: −1.02 to −0.24, p < 0.01) when compared to control group/pre-intervention. There were no significant effects on IL-6 and TNF-α, and no differences when compared to moderate-intensity training. Subgroup analyses indicated greater effectiveness in intervention duration, work-and-rest ratio, and work time were the significant moderators (p < 0.05). Conclusions: High-intensity interval training is effective for reducing CRP levels in children with obesity. Intervention duration, work-and-rest ratio, and work time can affect the intervention effects of HIT.

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