New findings
"It is the higher capacity to deliver fuel to muscles that athletes are interested in," said Dr. Federico Formenti, a physiology researcher at the University of Oxford and lead author of the new study. "However, it's not clear how long they should train at altitude or how high up they need to be to get the optimal benefits."
Formenti's team studied the effects of altitude training in patients with a rare genetic disorder, called Chuvash polycythemia or CP, and a group of equally fit people without CP. In people without the disorder, the body's reaction to high altitudes starts with a protein called hypoxia-inducible factor (HIF), which triggers a series of physiological changes. But in those with the disorder, a person's level of HIF remains elevated even when they are at sea level. This condition offered the researchers an opportunity to study the metabolic effects of permanently being in the "high-altitude" state.
The researchers asked volunteers to pedal a bike at a constant rate while the resistance was slowly increased. The results showed those with CP had to quit the test early and achieved a work rate that was 70 percent that of those without CP.
"We found that the metabolism of CP patients is different and leads to poorer physical performance and endurance," Formenti said. "Although this is a small study necessarily so because of there are so few people with the condition the results are striking. The differences seen in those with Chuvash polycythemia were large, and five patients were more than enough to see this effect."
Because the people with CP did more poorly than those without it, the researchers concluded that there are limits to the benefits of training at high altitudes, which also increases levels of HIF in the body.
So, optimizing the altitude training formula of how high to go and how long to stay there could be the difference between raising the Cup or going home early.
The research was published in the journal Proceedings of the National Academy of Sciences and was funded by the British Heart Foundation and the Wellcome Trust.