Blood doping is defined by WADA (World Anti-Doping Agency) as the misuse of techniques and/or substances to increases ones red blood cell count. Most commonly this involves the removal of two units (approximately 2 pints!) of the athletes blood several weeks prior to competition.
The blood is then frozen until 1-2 days before the competition, when it is thawed and injected back into the athlete. This is known as autologous blood doping. Homologous doping is the injection of fresh blood, removed from a second person, straight into the athlete.
A second method of blood doping involves the use of artificial oxygen carriers. Hemoglobin oxygen carriers (HBOC's) and Perfluorocarbons (PFC's) are chemicals or purified proteins which have the ability to carry oxygen. They have been developed for therapeutic use, however are now being misused as performance enhancer's.
Tests were introduced in 2004 which are capable of detecting the use of homologous transfusions and the use of artificial oxygen carriers. Although a suitable test has not yet been developed to detect autologous blood doping.
After the development of EPO, the use of blood doping fell considerably, however since the development of a test for EPO detection and the lack of testing for autologous doping, it is again on the rise.
Medical Uses of Blood Doping
Artificial Oxygen carriers are the only form of blood doping which have a medical use. They were developed for use in emergencies when there is no time for determining and cross-matching a patients blood-type for transfusion, when there is a high risk of infection, or simply when no blood is available.
Effects on Performance
Blood doping is most commonly used by endurance athletes, such as distance runners, skiers and cyclists. By increasing the number of red blood cells within the blood (and so increasing the haematocrit), higher volumes of the protein haemoglobin are present. Haemoglobin binds to and carries Oxygen from the lungs, to the muscles where it can be used for aerobic respiration. Blood doping therefore allows extra Oxygen to be transported to the working muscles, resulting in a higher level of performance, without the use of the anaerobic energy systems.
Studies have shown that blood doping can improve the performance of endurance athletes.
Side-Effects of Blood Doping
The following are side-effects which can occur in any form of blood doping:
- Increased blood viscosity (thickness)
- Myocardial infarction (heart attack)
- Pulmonary embolism (a blockage, which can be fat, air or a blood clot, of the pulmonary artery)
- Cerebral embolism (a blockage, formed elsewhere in the body, which becomes lodged in an artery within or leading to the brain)
- Cerebrovascular accident (stroke)
Homologous transfusions are prone to further side-effects:
- Allergic reaction
- Risk of blood-borne diseases (hepatitis C, B and HIV)