EPO, or Erythropoietin, is a hormone produced by the kidneys that plays a crucial role in the production of red blood cells. When oxygen levels in the body are low, EPO stimulates the bone marrow to create more red blood cells, which helps transport oxygen throughout the body. This process is essential for maintaining energy levels and overall health. In the world of sports, EPO has gained attention for its use as a performance-enhancing drug. Athletes sometimes misuse EPO to increase their endurance by boosting their red blood cell count. However, this practice is illegal and can pose serious health risks, leading to a crackdown by organizations like WADA (World Anti-Doping Agency).