Hemoglobin is an iron-containing protein in red blood cells that transports oxygen throughout the body. Blood doping involves transfusing additional red blood cells to boost oxygen-carrying capacity and endurance. While it can enhance performance, blood doping poses health risks like kidney damage and infections. It is considered cheating and banned by major sporting organizations. Detection methods aim to identify unusually high red blood cell levels or doping drug traces, though new techniques like high-altitude sleep chambers complicate regulation efforts.