Effects of high-intensity interval training on cardiorespiratory fitness and metabolic outcomes in type 2 diabetes: A systematic review and meta-analysis

ObjectiveThis study aimed to investigate the effects of high-intensity interval training (HIIT) versus different types of exercise or no exercise on peak oxygen consumption, muscle strength, health-related quality of life, and cardiometabolic risk factors in people with type 2 diabetes mellitus.Data SourcesWe searched in EMBASE, PubMed, Cochrane Central, Physiotherapy Evidence Database (PEDro), and SciELO for randomized controlled trials assessing the impact of HIIT in people with type 2 diabetes mellitus.Review MethodsStudy quality was evaluated using the PEDro scale, and certainty of evidence. We calculated mean differences, standardized mean difference and 95% confidence intervals.ResultsSixty-two studies (2204 participants) were included. Compared to control, HIIT increased peak oxygen consumption by 4.56 mL·kg^-1·min^-1 (95% confidence interval 3.54 to 5.58) and reduced glycosylated hemoglobin by 0.70% (95% confidence interval -0.88 to -0.51). Improvements were also observed in insulin resistance, systolic and diastolic blood pressure, lipid profile, body mass index, and fat mass. When compared with moderate-intensity continuous training, HIIT improved peak oxygen consumption (1.30 mL·kg^-1·min^-1; 95% confidence interval 0.28 to 2.43) and glycosylated hemoglobin (-0.12%; 95% confidence interval -0.24 to -0.01).ConclusionsHigh-intensity interval training improves peak oxygen consumption, glycosylated hemoglobin, insulin resistance, and various cardiometabolic risk factors in people with type 2 diabetes mellitus.