The first known form of hypoventilation occurred in the 1950s during training of the runners of Eastern Europe and former USSR. One of the most famous athletes to have used this method is Emil Zátopek, the Czech long-distance runner, four times Olympic gold medalist and former holder of 18 world records. Zátopek, who was a precursor in training, regularly used to run by holding his breath to harden his training and simulate the conditions of competition. However, at that time, the effects of hypoventilation training were completely unknown and the method was applied very empirically.