The 15th Athletics World Championships, which opened on August 22 in Beijing, China, present a significant challenge for the organisers. Allegations in early August of mass doping among athletes mean any untoward behaviour will pose a threat. According to media revelations, a third of endurance runners who won Olympic and world championship medals from 2001 to 2012 may have cheated by “blood doping”.
Also, more than 800 athletes are thought to have returned abnormal blood tests. The World Anti-Doping Agency uses a battery of blood and urine tests to determine if athletes are cheating. A key tool is the biological passport programme, which tests all athletes for doping and performance-enhancing drugs.
Blood doping: Blood doping increases the blood’s ability to carry oxygen. This can have a direct impact on VO2max, the measure of a person’s aerobic capacity. Ultimately, blood doping is one of the more effective illegal ways of improving endurance performance. Athletes “blood dope” by either using blood transfusions or specific drugs to increase their red blood cell count (haemoglobin). When they transfuse blood, they can re-infuse their own blood (autologous) or use blood from another person who serves as a donor (homologous).
And when blood is taken out of the body and used for transfusions, up to four components, including red blood cells, platelets, plasma and cryoprecipitated antihemphilic factor, are removed from the sample and then frozen. Typically the red blood cells are returned to the athlete’s body when the sample is re-infused, in order to increase their ability to carry oxygen.
When athletes re-infuse their own blood, there’s no direct way of detecting what they’ve done. But indirect detecting methods are available, such as measuring their total haemoglobin mass (red blood cell size) or metabolites of blood bag plasticisers (by-products of the container the blood is stored in). If the athlete transfuses someone else’s blood, drug testers can look directly at the antigen pattern of the red blood cells to detect doping. Since everyone has a different genetic code, doping is easily spotted when red blood cells present different genetic markers.
Erythropoietin (EPO): Another common method of doping is the use of recombinant human erythropoietin (rhEPO), which stimulates the production of red blood cells. Erythropoietin (EPO) is a hormone found in the blood; recombinant EPO is the artificial version. EPO’s ability to increase the number of red blood cells results in increase of oxygen in the blood, which boosts athletic performance.
One way athletes appear to be circumvent detection is by small, frequent use of EPO. In 2011, experts found frequent micro-dosing allows athletes to use rhEPO without abnormal changes in the blood variables. As the fight against doping continues, athletes appear to be continually searching for ways to elevate their performance and evade detection. Worse, some have found ways to beat the biological passport.
— www.theconversation.com
