Comparative effects of high-intensity and sprint interval training on cardiorespiratory fitness and body composition: a systematic review with meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 41306569 · doi:10.3389/fphys.2025.1668326
What was done
A systematic review and meta-analysis (PROSPERO CRD420251016362) synthesized 9 randomized controlled trials with 666 total participants to evaluate the effects of high-intensity interval training (HIIT) and sprint interval training (SIT). Primary outcomes were changes in VO2 max/VO2 peak and body fat percentage. Analyses used standardized mean differences (SMD) or weighted mean differences (WMD), stratified by health and training status (healthy/trained vs. overweight/obese).
What was found
Compared to controls, both interval training modalities combined significantly improved cardiorespiratory fitness (SMD = 1.54; 95% CI: 0.89 to 2.18; p < 0.00001) and reduced body fat mass (WMD = -3.45%; 95% CI: -5.04 to -1.87; p < 0.0001). In subgroup analyses, HIIT was more effective than SIT for cardiorespiratory fitness in overweight/obese individuals (SMD = -0.97; p = 0.0004), whereas SIT was more effective for fat loss in healthy or trained individuals (WMD = 5.85; p < 0.00001).
Why it matters
This review suggests the relative benefits of HIIT versus SIT depend on baseline fitness and body composition, supporting targeted exercise prescription based on an individual's starting health status.
Limits
The analysis included only 9 trials with 666 total participants across all subgroups. The abstract does not report study-level intervention lengths, specific exercise protocols, compliance, dietary control, or adverse events.
Cited by
- context The optimal interval duration for generating VO2 max adaptation is 3 to 8 minutes with a 1:1 work-to-recovery ratio.