The Ineos Grenadiers cycling team has faced scrutiny over their use of carbon monoxide rebreathing tests, a controversial technique that has raised concerns among cycling authorities. According to a recent report, the team began employing this method during a training camp in Spain in February 2025, just before new UCI rules were implemented. The frequency and setting of these tests were not in line with the governing body's recommendations and are now explicitly prohibited under UCI medical regulations. This comes as a surprise, as the UCI had previously issued non-enforceable guidelines on the practice. The team claims to have always followed UCI rules, but the timing of their implementation raises questions. The use of carbon monoxide rebreathing in cycling was first revealed during the 2024 Tour de France, where top teams were found to be using it for altitude training. This technique, established in the 1980s, allows for precise dosing of carbon monoxide into the lungs, aiding in medical and scientific research. However, its potential lethality and the team's timing have sparked debates about the ethical and safety implications of this practice.
