The comparison effects of aerobic continuous training and aerobic interval training on glycemic control and endothelial function in type 2 diabetes mellitus

The objective of this study was to compare the effects of continuous aerobic exercise training (CON) and interval aerobic exercise training (INT) on glycemic control and endothelium-dependent vasodilatation in patients with type 2 diabetes. A total of 43 participants with type 2 diabetes aged 50-70 years were stratified in parallel-group study and randomly allocated to the sedentary control, continuous aerobic training (CON), and interval aerobic training ( INT) groups. Exercise training programs were designed to yield the same energy expenditure/exercise session and included walking on treadmill for 30 or 40 minutes/day, 3 times/week for 12 weeks. Biological variables, health-related physical fitness, endothelial function and biochemistry variables between pre-test and post-test were analyzed by a paired t-test. One way analysis of variance was used to compare the variables among groups. Differences were considered to be significant at p < .05. The results of the present study were as follow : 1. Body mass, BMI, body fatness, waist-to-hip ratio, and heart rate at rest decreased and leg muscle mass and muscle strength increased (all p<0.05) significantly in both the CON and INT groups when compared with pre-test. 2. Fasting blood glucose and insulin resistance levels decreased (p<0.05) in both exercise groups but glycosylated hemoglobin levels decreased (p<0.05) significantly only in the INT group when compared with pre-test. 3. Maximal aerobic capacity, flow-mediated dilation, and cutaneous blood flow increased (all p<0.05) significantly in both exercise groups; however, the magnitude of improvement was greater (p<0.05) significantly in the INT group. 4. Malondialdehyde and von Willebrand factor decreased and glutathione peroxidase and nitric oxide increased significantly (all p<0.05) in the INT group. CON group showed no significant changes in these parameters. In conclusion, Both CON and INT were effective in improving glycemic control, aerobic fitness, and endothelium-dependent vasodilation, but the INT program appears to confer greater improvements than the CON program.