PARIS — Cyclists who dope themselves with EPO may not gain any performance advantage even though they are putting their health at risk, scientists said on Thursday.
In a review of the evidence, a team of European researchers scoffed at the entrenched notion that EPO gives cyclists an edge. They pointed out that the drug has many perils for those who use it illicitly, including blood clots that can cause strokes and heart attacks.
"Athletes and their medical staff may believe EPO enhances performance, but there is no evidence that anyone performed good experiments to check if EPO would actually improve performance in elite cyclists," said Adam Cohen, a professor at the Centre for Human Drug Research in the Netherlands.
EPO — erythropoietin — is a natural hormone, produced in the kidneys, which helps regenerate the red blood cells that transport oxygen around the body. A manmade version of the hormone is licensed for treating renal patients to help them combat anaemia.
EPO engulfed professional cycling, breeding a scandal that erupted this year when Lance Armstrong was stripped of his record seven Tour de France titles.
The big belief behind EPO is that it improves maximal oxygen uptake — known in scientific parlance as VO2 max — and thus boosts power output. But Cohen found no proof for this. In tests, cycling volunteers were usually assessed for VO2 max for just 20 minutes or so, a far cry from a five-hour grind of a cycling race.
In any case, said the study, VO2 max is only a minor factor in the performance of endurance cyclists.
Only small segments of professional cycling races are cycled at such severe intensities that VO2 max is decisive.
"There is no scientific basis to conclude EPO has performance-enhancing properties in elite cyclists," is the blunt conclusion of the study, which appears in the British Journal of Clinical Pharmacology.
"Additionally, the possible harmful side-effects have not been adequately researched for this population, but appear to be worrying at least."