The impact of high-intensity interval training on postprandial glucose and insulin: A systematic review and meta-analysis

We performed a systematic review and meta-analysis to investigate the effects of high-intensity interval training (HIIT) on postprandial glucose (PPG) and insulin (PPI) versus non-exercise control and moderate-intensity continuous training (MICT) in participants with both normal and impaired glucose.The PubMed, Scopus, and Web of Science electronic databases were searched up to October 2021 for randomized trials evaluating HIIT versus control and/or versus MICT on glucose and insulin AUC using oral glucose tolerance testing. Subgroup analyses based on intervention duration (short-duration < 8 weeks, moderate-duration ≥ 8 weeks), baseline glucose levels (normal glucose and impaired glucose) and type of HIIT (L-HIIT and SIT) were also conducted across included studies.A total of 25 studies involving 870 participants were included in the current meta-analysis. HIIT effectively reduced glucose [-0.37 (95% CI -0.60 to -0.13), p = 0.002] and insulin [-0.36 (95% CI -0.68 to -0.04), p = 0.02] AUC when compared with a CON group. Reductions in glucose AUC were significant for those with impaired glucose at baseline (p = 0.03), but not for those with normal glucose levels (p = 0.11) and following moderate-duration (p = 0.01), but not short-duration interventions (p = 0.18). However, there were no differences in glucose (p = 0.76) or insulin (p = 0.43) AUC between HIIT and MICT intervention arms.Our results demonstrated that both HIIT and MICT are effective for reducing postprandial glycemia and insulinemia, particularly by moderate-duration interventions, and in those with impaired glucose.