A time-efficient public health strategy: a systematic review and meta-regression on the comparable and dose-independent effects of sprint interval training vs. moderate-intensity continuous training for metabolic health

Abstract

Background: Promoting physical activity is a public health priority for managing metabolic dysfunction, yet "lack of time" remains a major barrier to adherence. Sprint interval training (SIT) has emerged as a time-efficient alternative to traditional moderate-intensity continuous Training (MICT), but its relative effectiveness and optimal dosage are unclear. This study aimed to compare the effects of SIT vs. MICT on glycemic control and insulin sensitivity, and to investigate the influence of training dose on these outcomes.

Methods: Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing SIT (≥2 weeks) against MICT in adults with metabolic dysfunction. A random-effects model was used to determine the mean difference (MD). A series of univariable meta-regression analyses explored whether the effects were moderated by SIT dose characteristics, including intervention duration, sprint volume, and weekly training load (metabolic equivalent of task [MET]-minutes).

Results: Thirteen RCTs (503 participants) were included. The pooled analysis revealed comparable effects between SIT and MICT on all primary glycemic outcomes, including glycated hemoglobin (HbA1c) (MD = -0.02%; 95% confidence interval [CI]: [-0.10, 0.07]; p = 0.624), homeostatic model assessment for insulin resistance (HOMA-IR) (MD = -0.08; 95% CI: [-0.27, 0.11]; p = 0.362), and fasting glucose (MD = 0.02; 95% CI: [-0.15, 0.20]; p = 0.774). Crucially, our meta-regression analyses found no statistically significant dose-response relationships. The comparable efficacy of SIT was consistent and not significantly influenced by variations in intervention duration, sprint volume, or weekly training load (p > 0.05 for all moderator analyses).

Conclusion: Our results indicate that SIT and MICT elicit similar improvements in markers of glycemic control for adults with metabolic dysfunction. These findings suggest SIT is a viable and time-efficient alternative to MICT for individuals with limited time availability. However, variability in SIT protocols and the presence of statistical heterogeneity warrant cautious interpretation of these findings.

Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/view/CRD420251118188.

Keywords: glycemic control; high-intensity interval training; insulin sensitivity; metabolicsyndrome; moderate-intensity continuous training; sprint interval training.