The Effects of Water-based Exercise Training in People with Type 2 Diabetes

PURPOSE: To investigate the effects of 8 wk of upright water-based exercise training in people with type 2 diabetes. METHODS: Thirteen participants with type 2 diabetes (54% male; 60.9 +/- 9.6 yr, mean +/- standard deviation) completed 8 wk of upright water-based exercise training at a moderate intensity (60%-80% of exercise test-derived maximum HR), for 1 h, three times a week (TG). Fourteen participants (64% male; 63.9 +/- 9.8 yr) acted as a control group (CG) who maintained their usual activities. Preintervention and postintervention, participants performed cardiopulmonary exercise testing to determine V O2peak and one-repetition maximum testing to assess muscular strength. Blood profiles were assessed with standard assays. Body mass index and waist/hip ratio were employed as measures of anthropometry. Endothelium-dependent (brachial artery flow-mediated dilation) and independent (glyceryl trinitrate-mediated) function were assessed using vascular ultrasound. RESULTS: Water-based training increased V O2peak (18.5 +/- 4.3 mL.kg.min to 21.5 +/- 5.4 mL.kg.min) (P = 0.002), overall muscle strength (123 +/- 44 kg to 139 +/- 43 kg) and leg strength (92 +/- 28 kg to 104 +/- 29 kg), compared with the CG (P = 0.001). The effect on pectoral strength (31 +/- 17 kg to 35 +/- 16 kg) was not significantly different to the CG (24 +/- 12 kg to 26 +/- 14 kg) (P = 0.08). No change was observed in anthropometry, blood profiles, or glyceryl trinitrate-mediated vascular function. Flow-mediated dilation was increased after training (6.1% +/- 2.4% to 6.5% +/- 3.0%), compared with controls who demonstrated a slight decrease (6.2% +/- 1.6% to 5.4% +/- 1.6%) (P = 0.002). CONCLUSIONS: Water-based circuit training was well tolerated and appears to be an effective exercise modality for improving aerobic fitness, strength, and vascular function in people with type 2 diabetes.