Altitude tent

From Wikipedia, the free encyclopedia

An altitude tent, also known as an altitude simulation tent or a hypoxic tent, is an enclosed living space which simulates high altitude by maintaining a lower oxygen concentration. It is used by endurance athletes and by high-altitude mountain climbers to stimulate the body's natural adaptations to altitude, including an increase in the number of red blood cells and enzymes. Red blood cells carry oxygen to the body; athletes benefit from increased delivery of oxygen to the muscles, and mountain climbers can avoid altitude sickness by better utilizing the diminished amount of oxygen found at higher altitudes.

The basic concept of living or training at altitude is to cause the body to adapt to the lower oxygen content by producing more oxygen-carrying red blood cells and hemoglobin. This improves the athlete’s ability to perform work, because more oxygen is available to the working muscles..

Sleeping in a simulated altitude environment allows the body to achieve some of the positive adaptations to altitude while still permitting the athlete to perform workouts at an oxygen-rich lower altitude where muscles can perform at their normal work level. An altitude tent is one way to expose the athlete to hypoxic air.

Rather than simulate altitude with low air pressure, the altitude tent remains at normal air pressure, substituting low concentration of oxygen for low pressure. While normal air contains 21% oxygen independent of altitude, the air in an altitude tent contains as little as 10% oxygen (the remainder being the inert gas, nitrogen). This is accomplished with a “hypoxic air generator” outside the tent pumping the conditioned air into the tent, displacing oxygen in the air entering the tent with nitrogen to reduce the oxygen content percentage. Most athletes use altitudes between 8,000 and 12,000 feet.

The tents themselves come in several styles. Unlike camping tents, altitude tents cannot have much ventilation, and often substitute clear plastic windows for nylon and mesh vents. Displaced air escapes the tent through small outlets, seams, or zippers. Air delivery can be through hose long enough to allow the generator to be placed in a different room, reducing noise. Some specially-designed tents can be placed over normal-sized beds to make sleeping comfortable.

One problem with altitude tents relates to build up of heat and humidity. Because of the use of plastic panels to reduce exchange with the room, heat and humidity can rapidly build up in an altitude tent. Some tents allow the use of air conditioners to maintain comfortable conditions. Carbon dioxide from exhaled air can also build up to dangerous levels if air flow is too low. Because of these problems, some athletes prefer using mask systems.

The ethics of the use of these devices by athletes has been discussed by the World Anti-Doping Agency (WADA), which alleges that it is equivalent to blood doping; however, on September 16, 2006, Dick Pound of the WADA announced that they will not at this time be prohibiting the use of altitude tents, barring any future reports of health problems.