Performance Enhancing Drugs – Blood Doping
Blood doping is an umbrella term for any technique by which athletes artificially increase their blood’s ability to transport oxygen. While blood doping is generally included under discussions of performance enhancing drugs, this method of performance enhancement need not involve the use of drugs at all. Nevertheless, the competitive advantages that blood doping can confer have led to all blood doping practices being banned by the World Anti-Doping Association (WADA) and most international sporting organizations.
The Benefits of Blood Doping
The body’s ability to deliver oxygen to muscles during exercise plays a tremendous role in athletic performance. Regardless of the amount of muscle mass that an individual possesses, the body’s ability to supply oxygen to those muscles will determine the length of time during which those muscles can function, or their endurance. With greater supply of oxygen, muscles take longer to feel tired and are able to perform at capacity for longer stretches of time.
Scientists estimate that the process of blood doping can improve an athlete’s endurance by up to five percent. Blood doping is particularly common in endurance sports such as cycling or distance running, where that five percent can have a significant impact on an individual’s overall performance.
Blood Doping Techniques
There are three primary techniques that athletes use to artificially increase their oxygen delivery capacity. Two of these methods involve increasing the body’s natural red blood cell count, while another involves the use of artificial carriers that can transport oxygen just as red blood cells do.
During the 1990s and early 2000s, the peptide hormone erythropoietin, or EPO, was the most common tool for blood doping. Peptide hormones are naturally secreted by human glands, and EPO is the hormone responsible for red blood cell production. By taking supplemental EPO, athletes are able to increase their red blood cell level-technically known as hematocrit-to well above normal.
Another method of blood doping is the use of synthetic oxygen carriers. These carriers are purified proteins or chemicals such as hemoglobin based oxygen carriers or perfluorocarbons that can transport oxygen through the blood stream.
The final common method for blood doping is through blood transfusions. Athletes may receive transfusions from a compatible donor, known as homologous transfusions, or transfusions of their own blood that was previously drawn, known as autologous transfusions.
With either method, transfusions are given shortly before a competition to give athletes an instant aerobic boost. In the case of autologous transfusions, the athlete’s blood must be drawn far enough in advance that the body has enough time to naturally replenish its red blood cell count to normal levels.
Detecting Blood Doping
The detection of blood doping has long been a challenge for anti-doping officials. However, a reliable test for EPO fist saw wide usage during the 2000 Summer Olympic Games in Sydney, Australia, and four years later the Athens Games saw the debut of tests for synthetic oxygen carriers and homologous transfusions.
Only autologous transfusions-transfusions of an athlete’s own blood-do not currently have a reliable test. As a result, some sports such as cycling do not allow athletes to have a hematocrit above a certain level, unless they can reliably prove that their hematocrit range is higher than normal.
The Risks of Blood Doping
All forms of blood doping carry the risk of significant side effects. EPO use and either homologous or autologous blood transfusions cause the blood to thicken. This thickening leads to a greater risk of serious consequences such as pulmonary or cerebral embolisms, which can lead to strokes or heart attacks. The misuse of EPO can also lead to a greater risk of heart disease.
Blood transfusions come with an addition set of risk factors. Since banned transfusions for athletes are rarely performed with the proper facilities and oversight, there is a greater chance that the blood may not be stored, handled, or screened properly. Homologous transfers carry the risk of viruses in the donor’s blood being passed on the athlete host, while autologous transfers may become contaminated or compromised if the blood is not correctly handled and stored.