The purpose of this project is to investigate the effect of physical training on the mitochondrial respiratory function in muscles of patients with T2D. Skeletal muscle biopsies will be taken before and after 10 weeks of physical training in patients with T2D and matched control subjects. Mitochondria will be isolated from the muscle biopsies, and respiratory function, free radical production and UCP3 will be determined. Furthermore, measures of maximal oxygen consumption (VO2max), heart rate and capillary lactate concentrations and carbohydrate and lipid oxidation will be determined partly to verify an increased aerobic capacity and partly to investigate the changes in these factors in T2D patients.