Abstract
Sprint interval training (SIT) has been proposed as a time-efficient strategy for improving cardiometabolic health. However, uncertainty remains about its effects on metabolic health. We systematically searched Web of Science, PubMed, Embase, Scopus, and the Cochrane Library for randomized controlled trials (RCTs) comparing SIT with no-exercise control or moderate-intensity continuous training (MICT). Three-level meta-analysis, subgroup analyses, and meta-regression were performed. Forty trials involving 1,460 participants were included. Compared with no-exercise control, SIT significantly improved glycemic outcomes, insulin responses, and lipid-related outcomes, although heterogeneity was substantial to considerable and some estimates were sensitive to study or effect-size removal. No significant differences were found between SIT and MICT at the outcome-domain level. Outcome-specific analyses favored SIT for fasting insulin, homeostatic model assessment of insulin resistance (HOMA-IR), low-density lipoprotein cholesterol (LDL-C), and total cholesterol (TC) versus no-exercise control, and for HOMA-IR versus MICT. Health condition moderated glycemic outcomes, while measurement type and exercise modality moderated lipid-related outcomes. Intervention duration, sprint duration, and number of sprints per session were not significant moderators. Evidence certainty was low to very low. SIT may improve metabolic outcomes compared with no exercise and produce broadly comparable effects to MICT, but findings should be interpreted cautiously because of heterogeneity, sensitivity, and limited evidence certainty.