High-intensity interval training for cardiometabolic health in adults with metabolic syndrome: a systematic review and meta-analysis of randomised controlled trials.

ABSTRACT

OBJECTIVE: To assess the effectiveness of high-intensity interval training (HIIT) compared with traditional moderate-intensity continuous training (MICT) and/or non-exercise control (CON) for modification of metabolic syndrome (MetS) components and other cardiometabolic health outcomes in individuals with MetS. DESIGN: Systematic review and meta-analysis DATA SOURCES Five databases were searched from inception to March 2024. STUDY APPRAISAL AND SYNTHESIS: Meta-analyses of randomised controlled trials (RCTs) comparing HIIT with MICT/CON were performed for components of MetS (waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), and fasting blood glucose (BG)) and clinically relevant cardiometabolic health parameters. Subgroup moderator analyses were conducted based on the intervention duration and HIIT volume. RESULTS: Out of 4819 studies, 23 RCTs involving 1374 participants were included (mean age 46.2-67.0 years, 55% male). HIIT significantly improved WC (weighted mean difference (WMD) -4.12 cm, 95% CI -4.71 to -3.53), SBP (WMD -6.05 mm Hg, 95% CI -8.11 to -4.00), DBP (WMD -3.68 mm Hg, 95% CI -5.70 to -1.65), HDL-C (WMD 0.12 mmol/L, 95% CI 0.04 to 0.20), TG (WMD -0.34 mmol/L, 95% CI -0.41 to -0.27) and BG (WMD -0.35 mmol/L, 95% CI -0.54 to -0.16) compared with CON (all p<0.01). HIIT approaches demonstrated comparable effects to MICT across all parameters. Subgroup analyses suggested that HIIT protocols with low volume (ie, <15 min of high-intensity exercise per session) were not inferior to higher volume protocols for improving MetS components. CONCLUSION: This review supports HIIT as an efficacious exercise strategy for improving cardiometabolic health in individuals with MetS. Low-volume HIIT appears to be a viable alternative to traditional forms of aerobic exercise.