Effects of Aerobic Exercise vs. Resistance Training on Endothelial Function in Women with Type 2 Diabetes Mellitus

BACKGROUND: There is controversy over whether aerobic or resistance exercise is more effective for improving endothelial function in type 2 diabetes mellitus (T2DM). This study was aimed to investigate the effects of an aerobic and resistance training program on endothelial function, and the influences of glycemic control, body weight changes, and aerobic capacity in T2DM. METHODS: Total 40 overweight women with T2DM were assigned into 3 groups: an aerobic exercise group (AEG, n=13), resistance exercise group (REG, n=12), and control group (CG, n=15), and followed either brisk walking for the AEG or resistance band training for the REG, 60 minutes per day, 5 days per week for 12 weeks with monitoring daily activity using accelerometers. We assessed endothelial function by flow-mediated dilation (FMD), and aerobic capacity by oxygen uptake at anaerobic threshold (AT_VO2) at baseline and following training program. RESULTS: The mean participants' age was 57.0+/-6.8 years, and body mass index (BMI) was 27.0+/-2.3 kg/m2. After intervention, FMD increased by 2.2+/-1.9% in AEG, which differed from REG and CG (P=0.002), despite of decreased body weight (BW) in both AG and RG (2.8+/-2.5%, P=0.002; 1.6+/-2.0%, P=0.017, respectively). A significant increased AT_VO2 and decreased HbA1c were found only in AEG. In all participants, FMD was changed with the significant relations to the AT_VO2 (r=0.348, P=0.035), but not to HbA1c levels or BW. CONCLUSION: Aerobic exercise appears to be more beneficial than resistance exercise for improving endothelial function in T2DM. In addition, aerobic capacity could be a better predictor of changes in FMD than BW and glycemic control.

The Correlations between Extremity Circumferences with Total and Regional Amounts of Skeletal Muscle and Muscle Strength in Obese Women with Type 2 Diabetes

BACKGROUND: Insulin resistance is related to central obesity and the amount of skeletal muscle. A simple and practical anthropometric marker for muscle mass is not known, although waist circumference (WC) is used as an indicator of abdominal obesity. The aims of this study were to investigate whether arm (AC) and thigh circumferences (TC) can be used as an indicator of muscle mass and if they are related to muscle strength. METHODS: A total of 110 obese (body mass index [BMI]> or =25 kg/m2) women with type 2 diabetes were enrolled, and WC, AC, and TC were measured. Abdominal visceral fat (AVF), subcutaneous fat (ASF), and total fat (ATF) were assessed by computed tomography, regional muscle (MM), and fat mass by dual-energy X-ray absorptiometry, muscle strength by one repetition maximum (1RM) of both extremities (chest and leg press) and insulin resistance by KITT. RESULTS: The mean age was 56.2+/-7.3 years, duration of diabetes was 4.2+/-4.4 years, and BMI was 27.2+/-2.8 kg/m2. WC was correlated with ATF, AVF, and ASF (r=0.728, P<0.001; r=0.515, P<0.001; r=0.608, P<0.001, respectively). Arm MM was correlated with AC (r=0.500, P<0.001), and leg MM with TC (r=0.291, P=0.002). Upper 1RM was related to AC/WC ratio (r=0.359, P<0.001), and lower 1RM was to TC/WC ratio (r=0.286, P=0.003). Insulin resistance had significant relations with AVF, WC, and total MM (r=-0.262, P=0.008; r=-0.217, P=0.029; r=0.160, P=0.031, respectively). CONCLUSION: The muscle mass was related to extremity circumferences, and muscle strength was to extremity/waist circumference ratio in obese women with type 2 diabetes.