It was a sensation during the Tour de France 2024. It became public that top riders such as Tadej Pogacar and Jonas Vingegaard had used carbon monoxide inhalation devices in preparation for the race. The gas is considered highly toxic, but can also be used as a blood doping agent. Experts believe that targeted inhalation of the gas could be used to replace at least a time-consuming and cost-intensive altitude training camp. For this reason, the world cycling organisation UCI banned the repeated inhalation of carbon monoxide at the beginning of the year. The WADA has now followed suit.
New passage in the anti-doping regulations
Subgroup M1.4 has now been added to class M1 (manipulation of blood and blood components) in the WADA Prohibited List. It now explicitly states at this point: "The non-diagnostic use of carbon monoxide (CO) is prohibited. Under certain conditions, it can increase erythropoiesis (formation of red blood cells)." Experts had called for the gas to be added to the WADA list, as it could clearly be a prohibited performance-enhancing method.
Diagnostic use remains permitted
The UAE and Visma teams, which made the headlines around the 2024 Tour, said at the time that they had only used the inhalation method to measure the effects of altitude training. This remains permitted: "The use of carbon monoxide for diagnostic purposes, such as the determination of total haemoglobin mass or the diffusion capacity of the lungs, is not prohibited under the supervision of a medical or scientific professional," the anti-doping regulations now state.
Proof of doping remains difficult
Despite the ban, the application presumably remains a grey area, as TOUR found out last year in response to enquiries (see article). As far as is publicly known, there is no detection method. Especially as carbon monoxide can also be inhaled unintentionally through exhaust fumes, as in heavy road traffic. The crux of the matter: detecting doping could be difficult with carbon monoxide. "If you do it right, it's difficult to detect. You would have to catch someone in the act," says Freiburg toxicologist Professor Volker Auwärter during the discussions last year when asked by TOUR. Athletes would therefore have to be caught red-handed despite the ban and proof would have to be provided that the inhalation was not carried out for diagnostic purposes and without professional supervision.
Andreas Kublik
Editor
