High-intensity interval training and continuous glucose monitoring-derived glycemic outcomes in adults with type 2 diabetes: a systematic review and meta-analysis

Background: Type 2 diabetes (T2D) is characterized by chronic hyperglycemia and marked within-day glucose fluctuations. Compared with conventional glycemic markers, continuous glucose monitoring (CGM)-derived metrics provide complementary information on overall glycemic exposure, postprandial responses, and glycemic variability. Although high-intensity interval training (HIIT) has shown promise for improving glycemic control in T2D, its effects on CGM-derived outcomes have not been systematically synthesized. Objective: To systematically review and meta-analyze the effects of HIIT on CGM-derived glycemic outcomes in adults with T2D, compared with non-exercise control (CON) or other exercise interventions. Methods: PubMed, Embase, Web of Science, the Cochrane Library, and EBSCOhost were searched from inception to January 26, 2026. Interventional studies comparing HIIT with CON or other exercise interventions and reporting CGM-derived outcomes were included. When data were suitable for quantitative pooling, pooled estimates were calculated from change-from-baseline values using fixed- or random-effects models. Risk of bias was assessed using RoB 2, RoB 2 for crossover trials, or ROBINS-I, and certainty of evidence was evaluated with GRADE. Results: Twelve studies involving 177 participants were included. Compared with CON, HIIT reduced 24-hour mean glucose, postprandial glucose, and time spent in hyperglycemia, while its effect on mean amplitude of glycemic excursions (MAGE) remained uncertain. Compared with moderate-intensity continuous training (MICT), HIIT further reduced 24-hour mean glucose and time spent in hyperglycemia, but no significant between-group difference was found for MAGE. Overall certainty of evidence ranged from very low to low. Conclusions: HIIT may improve selected CGM-derived glycemic outcomes in adults with T2D, particularly postprandial glucose and hyperglycemic exposure. Compared with MICT, HIIT may offer additional benefits for reducing 24-hour mean glucose and hyperglycemic time. However, confidence in these findings is limited by the small number of studies, methodological limitations, and heterogeneity.