There's no evidence that blood-boosting drugs give cyclists like Lance Armstrong an advantage in races like the Tour de France, a Dutch research team has found. The accounts of super-powers from athletes, coaches and trainers don't stand up to the scientific rigors of a controlled study, the team says, something the researchers propose to do themselves.
Artificial versions of erythropoietin, often called EPO, are used to treat people with anemia by stimulating the body to produce more of its own red blood cells. These extra cells carry more oxygen from the lungs to the allow the body to do more work, such as riding a bike uphill.
EPO-stimulating drugs are banned by sports authorities, and Armstrong was stripped of his seven Tour titles because of evidence of his use of EPO and other drugs.
These doping scandals have given EPO a bum rap, according to Adam Cohen, professor of clinical pharmacology at the University of Leiden in the Netherlands.
"Here in our practice, we use EPO to treat patients, and we got increasingly worried about scientific evidence being very low," he told Discovery News. "People are having strong opinions about EPO turning average cyclists into champions."
In a review study published today in the British Journal of Clinical Pharmacology, Cohen and his colleagues sifted through existing studies of EPO's effect on athletic performance. His main complaint is that these studies did not use elite athletes, rather study subjects who were "moderately trained athletes." As a result, the effects of EPO in high-level races have not been well understood, he explained.
"If you talk to cyclists, they say before EPO I went slower and then I could keep up," Cohen said. "But you know there are so many other things that happen: training levels, weather, strategy and tactics during a race, for example. That's why we like to do a placebo-controlled trial."
Cohen — who is also CEO of the Center for Human Drug Research, a testing lab for pharmaceutical firms in Leiden — proposes an EPO trial on a cycling team during a training camp, which usually occurs during the winter off-season between November and February.
"Cyclists are depicted as criminals, and they are under tremendous pressure to perform," he said. "They hear about it from doctors. It's much more fair that you know how it works. Our advice is to do the test. Take a group of real cyclists and allow them to use EPO."
One sports medicine expert believes Cohen's paper has missed the mark.
While it's true that few top-level cyclists or endurance athletes have participated in clinical trials to administer EPO drugs, that doesn't mean they don't work, said Michael Joyner, anesthesiologist at the Mayo Clinic in Rochester, Minn. Joyner studies the physiology of elite athletes and developed models of human performance.
There have been many studies showing that EPO boosts the level of VO2 max, or the maximum amount of oxygen taken up and used by the body.
"It's like a red line in a car," Joyner said about the difference between elite athletes and those participating in the previous EPO studies. "The red line is the same, but if you give them more horsepower (in this case EPO), you're going to go faster," said Joyner.
Some sports authorities in the 1980s said that there was no evidence that steroids enhanced athletic performance, despite athletes claims to the contrary, Joyner noted. Once the studies were done, "it was clear that (steroids) worked," he said.
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