is the legal version of blood doping. Instead of injecting the blood before competition or take drugs to stimulate the production of red blood cells that carry oxygen, many endurance athletes spend time in the thin air of high altitudes. The idea is to get their muscles to use oxygen more efficiently, so that when they return to lower altitudes, they have an edge over their competitors. But a new study of patients with a genetic disease that makes the body act as if they are still living at high altitude suggests that too much "altitude doping" is not beneficial and may even hurt performance.
the body reacts to the thin air at high altitude by producing proteins of the family of hypoxia-inducible factors (HIF). HIF stimulates the production of red blood cells and capillaries built to provide more oxygen in the muscles. Yet some people have a rare genetic disease in which HIF does not decompose, so that the levels are still high, as if they spent their days in the mountains. "In the UK, as far as we know, no more than 20 of these patients," says physiologist Federico Formenti of Oxford University in the UK.
To see what happens to people who have too much HIF, Formenti and colleagues recruited five patients and five healthy people at the university for two days of testing. volunteers rode vigorously on a stationary bike, ankle flexed position lying in a machine that measures an index of fatigue in the muscle, and had muscle biopsies taken. the researchers found that patients are not able to exercise as hard as the healthy controls because their muscles n 'using energy more efficiently Even very light exercise the tired quickly
patients have few symptoms... they are usually diagnosed after a routine blood test for elevated levels of hemoglobin one subjects was still a professional cricketer. "We had a laugh, saying cricket is not really a sport you do not have to run for a long time," says Formenti. He thinks that these patients can be a sports disadvantage because having too HIF blood has other effects that outweigh the benefits of more red blood cells and many capillaries.
Theoretically, athletes who train for long periods of time at high altitude would not be different from these patients, Formenti said. And that means the long-term training at high altitudes could actually be against-productive for athletes who have to run, bike or swim for extended periods, reports online today in the team Proceedings of the national Academy of sciences .
"But really, right now, nobody does this kind of training," says exercise physiologist Michael Koehle of the University of British Columbia in Canada. Athletes generally do not spend all their time at high altitude. Instead, he said, many now dieting called "live high, low gear." They sleep in altitude, or in a tent filled with air that is low in oxygen, and form below. yet Koehle said the study could help researchers refine sport-altitude training regimens by showing what could happen if athletes spend too much time in the mountains. the research "highlights why" live high, the elevated train "is not the best strategy for altitude training."
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