The effect of aerobic training on glycemic control, fitness, and cardiovascular risk factors in patients with mild and severe type 2 diabetes

Aim. Type 2 diabetes or non-insulin dependent diabetes mellitus (NIDDM) is highly related to obesity and inactivity. There is tremendous potential for improving glycemic control and insulin sensitivity, and managing cardiovascular risk factors by improving the physical activity among individuals with type 2 diabetes. We assessed the effect of an 8-week aerobic exercise program on cardio-respiratory fitness, plasma glucose, insulin concentration and lipid profile in patients with mild and severe NIDDM. Methods. Twenty four middle-aged male subjects with type 2 diabetes (age 46.9+/-7.8 yrs; height 165.2+/-5.5 cm; weight 73.5+/-12.2 kg; VO2max 40.3+/-6.5 mL/kg/min) participated in this study. Subjects were divided into high glycemic (HG) (mean plasma glucose concentration 217.8+/-25.5 mg/dl; N.=12) and low glycemic (LG) (mean plasma glucose concentration 149.9+/-20.2 mg/dl; N.=12) groups. The training program (45 min moderate intensity cycling with 60-70% HRR) was carried out 3 times per week for 8 weeks. Maximal oxygen consumption, blood pressure, blood lipids, plasma glucose and insulin concentration were measured before and after training program. Results. Nineteen subjects completed the study. VO2max increased significantly in both groups (P<0.05). Blood glucose concentration reduced significantly in the HG group (P<0.05), but this reduction was not statistically significant in the LG group. In general, low density lipoprotein (LDL) and triglyceride levels did not change significantly after training in both groups. High density lipoproteins (HDL) increased significantly in the HG group (P<0.05) but not in the LG group. Body weight, BMI, and body fat percent decreased significantly in both groups (P<0.05). Furthermore, the comparison of relative changes in physiological parameters between the two groups did not indicate significant differences. Discussion and conclusion: It can be concluded that aerobic training improves glycemic control, lipid profile, cardiorespiratory fitness, and body composition in type 2 diabetic men, and that this improvement is greater in high glycemic patients.