Blood doping usually involves the hormone growth factor, erythropoietin (EPO), which stimulates red blood cell formation in the bone marrow. Although it occurs naturally in the body, DNA technology can be used to produce EPO in the lab and then injected under the skin.
Why are red blood cells so important?
Red blood cells, or more specifically the haemoglobin (Hb) protein of the red blood cell, binds oxygen in the lungs and carries it to muscles throughout the body. One of the major limiting factors in endurance exercise is oxygen delivery to the working muscles. The more oxygen carrying capacity an athlete has, the better the athlete’s endurance.
How do scientists detect the use of EPO?
The volume of the red cell population in the blood is known as the haematocrit (HCT) and is normally between 41-50% in men, and 36-44% in women. Haemoglobin concentration can also be measured and should fall between 14-17g/dL in men, and 12-15g/dL in women. If blood tests detect high HCT or Hb values, it can indicate the use of EPO. Occasionally, athletes have naturally high HCT or Hb measurements, so testing over extended time periods is essential to determine exceptional values for the individual athlete.
The dangers of EPO doping
Excessive use of EPO can make blood more viscous; putting a strain on the heart muscles and has in many cases led to heart failure. The sport probably most associated with EPO is cycling but many endurance sports including rowing, distance running, triathlons and horseracing have had their fair share of scandal.