The International Olympic Committee will act with “zero tolerance” should allegations of widespread doping in athletics be proven, says president Thomas Bach.
The Sunday Times published data from 5,000 athletes, which it says reveals an “extraordinary extent of cheating”.
The data belongs to the International Association of Athletics Federations.
Bach said: “At this time we’ve nothing more than allegations and we have to respect the presumption of innocence.”
The blood-test data, covering the period between 2001 and 2012, was leaked by a whistle-blower to a German broadcaster and the Sunday Times.
“If there should be cases involving results at Olympic Games, the IOC will act with zero tolerance with our usual policy,” said Bach.
What are the claims?
The Sunday Times and German broadcaster ARD/WDR obtained access to the results of 12,000 blood tests from 5,000 athletes.
The files – seen by the BBC – show a third of all medals in endurance events (146, including 55 golds) at Olympics and World Championships were won by athletes who recorded suspicious tests, according to independent experts who have analysed the data.
More than 800 athletes – one in seven of those named in the files – recorded blood tests described by one of the experts as “highly suggestive of doping or at the very least abnormal”.
The data is not proof of doping – but the revelations raise more serious questions over whether the sport is doing enough to combat cheating.
What is blood doping?
Sports nutritionist Eleanor Jones says blood doping can help endurance athletes by increasing their ability to transport oxygen around the body.
She told BBC Radio 5 live: “It works like giving blood, except that after you’ve replaced that donation naturally in your body, you then reinfuse the blood that you removed originally, so you might have 110% of your normal blood volume.”
