Since SGLT-2 inhibitors have been recently demonstrated to ameliorate aerobic fitness in T2D subjects both without HF [48] and with HFpEF [49], one can speculate that the hemoconcentration with increased hemoglobin obtained with their pharmacological effect might increase Δ(a-v)O2 and partly explain the increased whole-body oxygen uptake. Here, SLC5A2 is linked to type 2 diabetes mellitus.