Blood doping is defined by the World Anti-Doping Agency (WADA) as the use of products that enhance the uptake, transport, or delivery of oxygen to the blood. Blood doping was a relative latecomer to emerge into the media glare of international athletics from the underworld of illegal performance-enhancing techniques. Unlike old-fashioned stimulants such as benzedrine or caffeine, or the numerous varieties of muscle-building anabolic steroids available to athletes since the 1960s, such as nandralone, blood doping seemed to be more of a gray art than a black one.
The more muted response in international athletics to blood doping practices has its origins with Finnish distance runner and four-time Olympic gold medalist Lasse Viren, the man believed to be the first successful practitioner of increasing his red blood count to correspondingly improve his body's ability to transport oxygen. After winning the 5,000-m and 10,000-m races at the 1972 Olympics, Viren raced with indifferent results in events leading up to the 1976 Olympics. At the games, Viren repeated as the gold medalist in his 1972 events, setting a world record in the 10,000-m event. Two days later, Viren finished fifth in the marathon (26.2 mi [42.2 km]), despite never having run a marathon before.
Viren's astounding achievement led many observers to conclude that Viren had done something illegal to have so dramatically boosted his performance. Long after the events of the 1976 Olympics, it was determined that Viren had likely aided his performance through blood doping, acts that were not then illegal under Olympic rules: blood doping would not be banned until 1986.
Besides the WADA definition of blood doping as the use of products that enhance the uptake, transport, or delivery of oxygen to the muscles, blood doping is also the use of blood or red blood cell products, of any origin, other than for legitimate medical treatment. Blood doping may be illegally used to increase red blood cell mass in an attempt to improve the amount of oxygen that can be delivered to the muscles in endurance events. Examples of products that enhance the uptake, transport, or delivery of oxygen include, but are not limited to, erythropoietin-modified hemoglobin products (or related substances), such as hemoglobin-based blood substitutes.
Blood doping is an expression that conjures visions of injecting or introducing foreign material into the blood system. A more accurate term to describe the practice might be blood building. At its most elemental, blood doping is a process by which the amount of erythrocytes (red blood cells) is artificially increased. Red blood cells contain hemoglobin, a red-colored protein that is rich in iron. The hemoglobin within each red blood cell is the carrier of oxygen within the bloodstream. In sports such as distance running, cycling, and cross-country skiing, the body must rely primarily upon its aerobic energy system (also known as the mitochondrial energy system) to sustain the activity. The oxygen inhaled is used by the body to breakdown glucose (a sugar that initially is stored in either the muscles or the liver) into energy. The greater volume of oxygen that can be transported by the hemoglobin in the red blood cells, the more efficient the energy conversion process within the body. An increase in the number of red blood cells is an increase in this efficiency.
The body will naturally increase the production of red blood cells in two circumstances. When the body is at a high altitude, there is less oxygen available to it than at sea level; as a consequence, the kidneys trigger the production of a hormone known as erythropoietin (EPO), which will in turn stimulate the body to produce a larger number of red blood cells. The body will also increase the amount of red blood cells, over time, where the muscle mass of the body has been increased and is subjected to strenuous training. The additional muscle mass creates a requisite need for greater energy, requiring additional oxygen to be transported.
There is no question that the increase of red blood cells in an athlete's system will likely improve athletic capacity to transport oxygen, and therefore the athlete functions with greater efficiency in competition. Blood doping, which is also known by the medical term induced erythrocythemia, has involved two techniques. Autotransfusion physically removes the blood from the bloodstream of the athlete and stores it to be returned to the system at a later time. The other technique of blood doping is the injection of a synthetic form of EPO.
A typical autotransfusion will be performed between two and three months prior to the target competition. The process begins with the withdrawal of between approximately 500 ml and 1,800 ml of blood from the athlete. The blood is placed in a centrifuge, a machine that separates the plasma, the fluid component of blood, and the red blood cells. The plasma is immediately returned to the athlete through an intravenous procedure to help maintain an optimum fluid level. The red blood cells are packaged and placed in frozen storage.
Prior to the target competition (typically between one to seven days in advance), the red blood cells will be intravenously returned to the body. Research regarding the effect of autotransfusion techniques suggests that the red blood count will be increased by up to 20%.
In some instances, this form of blood doping has involved the athlete receiving the red blood cells of another athlete who has the same blood type.
The athlete's chief difficulty before competition with the autotransfusion process was the likelihood of anemia (a shortage of iron in the blood), resulting from the removal of a significant amount of red blood cells, which would make continued high-level training for the target competition difficult. The intravenous process also carries the risk of the needles or equipment being shared, and the consequent exposure to contagious blood-borne disease such as HIV.
Further, the introduction of the large volume of red blood cells through autotransfusion places the athlete at risk of having blood that will clot too readily, which increases the chance of a stroke, heart attack, or pulmonary embolism (blood clots in the lungs). Further, the likelihood of dehydration occurring during an endurance event is high; dehydration reduces fluid levels, with a corresponding impact on blood volume, which makes the increased viscosity, or thickness, of the blood more pronounced.
With the development of synthetic EPO in the mid-1980s, the injection of this hormone replaced autotransfusion as the preferred method to increase red blood cell counts in an athlete. EPO stimulates the body's bone marrow to produce more red blood cells. The effects of EPO are substantially the same as those achieved by autotransfusion.
EPO had been an especially attractive blood doping technique because a reliable test to detect it has only existed since 2000. As with all elements of the efforts of international anti-doping regulatory agencies such as WADA, for every test designed to detect the presence of illegal substances in the bodies of athletes, parallel forces are seeking ever-ingenious ways to foil the testers.
Since the EPO test was first proven effective in 2000, a number of products have been developed to mask the presence of EPO, through seemingly expanding the plasma level in the blood. Plasma expanders, as they are known, represent a further testing target in EPO usage.
EPO has become a focal point in several investigations into illegal blood doping. There has been a number of high-profile investigations regarding prominent international cyclists, including Tyler Hamilton and Lance Armstrong. Three Olympic cross-country skiers from Finland tested positive for a variant of EPO, darbepoetin, at the 2002 Winter Olympics. Testing is carried out on one of two reasons: to determine whether EPO is present in the urine of the athlete, or to measure the level of hemoglobin (red blood cell protein) in the blood in an effort to assess whether the level is within normal ranges. Current EPO testing is not susceptible to either masking techniques or false/positive results.
One variation on the use of EPO was a scheme disclosed during the 2002 Tour de France competition by Spanish cyclist Jesús Manzano. Manzano alleged that he was approached by his team to use the blood of a relative who had taken EPO, and thus Manzano himself obtain the benefit of red cell-enriched blood without risking a positive test for the hormone itself.
Blood doping and EPO usage represent an attitudinal shift in sport ethics that has coincided with the creation of WADA and with the heightened interest in the illegal use of all forms of performance-enhancing substances. From the accomplishments of Lasse Viren in 1972 and 1976, the general societal view of cheating in athletics has become broader and less tolerant. Blood doping is a less dramatic, and arguably more natural, performance enhancement than using anabolic steroids; both are now clearly perceived as violations of the spirit of what athletic competition must be.