The scandals that plagued the 1998 Tour de France largely surrounded the systematic abuse of the synthetic hormone EPO to improve performance. Early in The Tour, Team Festina cyclists Alex Zuelle and Laurent Dufaux admitted taking EPO, and their team director confessed organizing doping under medical control. While the popular press expressed shock over the widespread use of EPO among top cyclists, those close to the sport indicated that EPO abuse has been pervasive in the top echelon of cycling for the past decade.
What is EPO?
EPO (short for erythropoietin) is a hormone secreted by the kidney that stimulates the bone marrow to increase red blood cell production. The primary benefit of altitude training is an increase in the natural production of EPO which increases the hemoglobin content of the blood. Oxygen is transported in the blood attached to hemoglobin. An increase in EPO, therefore, leads to an increase in the oxygen carrying capacity of the blood. More oxygen in the blood means more oxygen reaches the muscles for aerobic energy production, which enhances performance for long distance runners, cyclists, and other endurance athletes.
There are two illegal ways to increase the oxygen carrying capacity of an athleteís blood. One is to blood dope, which was the best available technology in the 1970ís and most of the 1980ís. Blood doping involves removing and storing a liter of your own blood, waiting a few weeks until your body has restored your red blood cell count and then re-injecting the stored red blood cells. Blood doping requires a reduction in training quality after the blood is removed, and is a fairly complicated procedure.
The modern way to illegally increase the oxygen carrying capacity of the blood is to inject the synthetic version of EPO. This hormone is produced synthetically to treat patients with kidney failure, cancer, and AIDS. For the past 10 years, a portion of the synthetic production of EPO has made its way into the hands of athletes. Earlier this year, former Belgian cycling champion Eddy Planckaert confessed taking EPO in 1991, and said that during the last 2 years of his career (1990 and 91) many riders were using EPO. Along with the performance benefits of EPO, however, came a spate of controversial deaths among top-level cyclists. Between 1987, when EPO became available in Europe, and 1990, 18 Dutch and Belgian cyclists died suddenly, raising suspicions that naive users did not realize they were playing with fire.
Why is EPO dangerous?
The same effect that improves endurance performance also risks the safety of the user. By increasing the thickness of the blood, EPO increases the risk of blood clotting which can block blood vessels causing a heart attack or stroke. Use of EPO also causes hypertension, and can lead to seizures and congestive heart failure. Sport is about testing limits. Unfortunately, in the case of EPO the limit being tested is how high the red blood cell content of the athleteís blood can increase before blood flow is impaired and the athlete dies.
Hematocrit is the proportion of the blood that is made up of red blood cells. Normal hematocrit levels are approximately 40-50% in men and 37-47% in women. EPO can boost hematocrit well above this range. As the athlete becomes dehydrated during training or racing, blood volume is reduced, further increasing hematocrit and the bloodís resistance to flow. During a marathon, the hematocrit of a non-doped runner may increase from 45 to 55. There is no set value at which a high hematocrit becomes dangerous, but the risk increases geometrically at hematocrit levels above 55%. If an EPO-doped marathoner starts the race at 52, his hematocrit could climb above 60 during the race.
Can EPO be detected?
Development of a valid and reliable test to detect synthetic EPO was a major priority of the International Olympic Committee leading up to the 2000 Olympics. Test development has taken many years due to the difficulty in producing an antibody that can distinguish synthetic EPO from the naturally-produced hormone, and because the half-life of synthetic EPO in the blood is only 6-8 hours. EPO testing is now valid and reliable, and is being used more and more in international sport.
There is no question that injecting synthetic EPO can improve performance for distance runners and other endurance athletes. Given the widespread use among cyclists, we would be naive to think that EPO abuse is not also prevalent in our sport.
(This column originally appeared in Running Times Magazine.)