Michael Shermer examines The Doping Dilemma, specifically in cycling, and describes the immense advantage from using recombinant erythropoietin (r-EPO) to stimulate the production of red blood cells:
One of the subtle benefits of r-EPO in a brutal three-week race like the Tour de France is not just boosting HCT levels but keeping them high. Jonathan Vaughters, a former teammate of Armstrong’s, crunched the numbers for me this way: “The big advantage of blood doping is the ability to keep a 44 percent HCT over three weeks.” A “clean” racer who started with a 44 percent HCT, Vaughters noted, would expect to end up at 40 percent after three weeks of racing because of natural blood dilution and the breakdown of red blood cells. “Just stabilizing [your HCT level] at 44 percent is a 10 percent advantage.”Scientific studies on the effects of performance-enhancing drugs are few in number and are usually conducted on nonathletes or recreational ones, but they are consistent with Vaughters’s assessment. (For obvious reasons, elite athletes who dope are disinclined to disclose their data.) The consensus among the sports physiologists I interviewed is that r-EPO improves performance by at least 5 to 10 percent. When it is mixed in with a brew of other drugs, another 5 to 10 percent boost can be squeezed out of the human engine. In events decided by differences of less than 1 percent, this advantage is colossal.