The latest allegations of wide-scale blood doping in athletics have been described as "incredibly damaging" by a British Olympian.
Roger Black, former 400m silver medallist, also said that the claims made it very hard for athletes to defend the sport.
He was speaking after the revelation that one third of Olympic and world championships medals - including 55 golds - won by athletes in endurance events were awarded to competitors with suspicious doping test results.
"It is incredibly damaging, because for those of us who love the sport, those of us who perform at the highest level, it is very frustrating.
"It becomes so much harder to defend the sport," Mr Black told ITV's Good Morning Britain.
The World Anti-Doping Agency (Wada) said it had been "very alarmed" by claims, which also alleged that more than a third of the world's fastest times in endurance events were recorded by athletes whose tests have triggered suspicion.
The latest claims have come to light as a result of data obtained by the Sunday Times and German broadcaster ARD/WDR.
They have had access to a database containing more than 12,000 blood tests from 5,000 athletes and which it claims reveals "the extraordinary extent of cheating by athletes at the world's most prestigious events".
Responding to a documentary highlighting the claims broadcast by ARD, Wada president Sir Craig Reedie said: "Wada is very disturbed by these new allegations that have been raised by ARD, which will, once again, shake the foundation of clean athletes worldwide."
He also announced that given the nature of the allegations, they would be handed over immediately to the organisation's Independent Commission for further investigation.
The data, which belongs to the IAAF but was released by a whistleblower, has been analysed by two leading anti-doping experts for the Sunday Times - scientist Robin Parisotto and exercise physiologist Michael Ashenden.
According to them, the leaked information reveals that more than a third of medals have been won in endurance events at the Olympics and world championships by athletes who have recorded suspicious tests. The newspaper claims none of those medals has been taken away by the authorities.
It is also claimed that a top UK athlete is among seven Britons with "suspicious" blood scores, while 10 medals were won at the London 2012 Olympics by athletes who have reportedly recorded dubious test results.
A statement on the IAAF's website said: "The IAAF is aware of serious allegations made against the integrity and competence of its anti-doping programme.
"The relevant allegations were broadcast on WDR (ARD) in Germany and have been repeated in an article in the Sunday Times newspaper.
"They are largely based on analysis of an IAAF Data Base of private and confidential medical data which has been obtained without consent. The IAAF is now preparing a detailed response to both media outlets and will reserve the right to take any follow up action necessary to protect the rights of the IAAF and its athletes."