Role of exercise intensity on GLUT4 content, aerobic fitness and fasting plasma glucose in type 2 diabetic mice.

Type 2 diabetes mellitus (T2D) results in several metabolic and cardiovascular dysfunctions, clinically characterized by hyperglycaemia due to lower glucose uptake and oxidation. Physical exercise is an effective intervention for glycaemic control. However, the effects of exercising at different intensities have not yet been addressed. The present study analysed the effects of 8 weeks of training performed at different exercise intensities on type 4 glucose transporters (GLUT4) content and glycaemic control of T2D (ob/ob) and non-diabetic mice (ob/OB). The animals were divided into six groups, with four groups being subjected either to low-intensity (ob/obL and ob/OBL: 3% body weight, three times/week/40 min) or high-intensity (ob/obH and ob/OBH: 6% body weight, three times per week per 20 min) swimming training. An incremental swimming test was performed to measure aerobic fitness. After the training intervention period, glycaemia and the content of GLUT4 were quantified. Although both training intensities were beneficial, the high-intensity regimen induced a more significant improvement in GLUT4 levels and glycaemic profile compared with sedentary controls (p < 0.05). Only animals in the high-intensity exercise group improved aerobic fitness. Thus, our study shows that high-intensity training was more effective for increasing GLUT4 content and glycaemia reduction in insulin-resistant mice, perhaps because of a higher metabolic demand imposed by this form of exercise.