Introduction: High-intensity interval training (HIIT) and moderate-intensity continuous training (MCT) in combination with metformin in diabetic patients is likely to be effective. This research aimed to investigate the possible role of HIIT and MCT training alone and also in combination with metformin on biochemical factors and lipid profiles in diabetic and healthy rats.    
Materials and Methods: Sprague-Dawley rats were allocated randomly into nine groups (in each group n = 5). Streptozotocin and nicotinamide were used to induce diabetes in target rats. Special diets were given to all groups of rats and exercise protocol was performed one time per week for 8 weeks. Rats received metformin (200 mg/kg) daily by gavage. The biochemical factors and serum lipid profiles were measured. Data analysis was performed using SPSS software and the significance level was considered at P < 0.05.     
Results: The lowest serum glucose and insulin levels among diabetic rats belonged to the diabetic group who received metformin and performed HIIT training (P < 0.05). Diabetic groups that performed HIIT and MCT training compared with the diabetic group that consumed metformin alone had lower HbA1c levels, which this difference was not significant (P < 0.05). The lowest triglyceride level among the treated diabetic groups was in the group that received metformin and performed HIIT training (P < 0.05). The results of HDL, LDL and cholesterol changes were similar to those found for triglyceride.     Conclusion: The study showed that both HIIT and MCT exercise, even in the absence of metformin, significantly reduce some biochemical factors and lipid profile levels as well as improve body weight in the diabetic rats under treatment with metformin compared with the diabetic control group.