In both healthy lean and obese individuals and in patients with T2D, exercise training improves insulin sensitivity [20,23,24,25,26] and increases the mitochondrial oxidative capacity in skeletal muscle by enhancing mitochondrial biogenesis [20,27,28], mainly through activation of peroxisome proliferator-activated receptor-γ co-activator (PGC)-1α [29,30,31]. This evidence concerns the gene INS and type 2 diabetes mellitus.