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Oxygen, and AMS Part I of II: The Hypoxic tent and pre-acclimatization 
Besides Dr. Gamow’s Altitude bed, another option is available to pre-acclimatize yourself for a trip to high-altitude – Hypoxico’s tent system. Explorersweb had the opportunity to talk with Shaun Wallace, Hypoxico’s Vice-President. His background is in the elite cycling world and Shaun was an innovator in the train-low, sleep-high revolution – testing different techniques early on, “it started from personal interest – I was looking for something to give me better performance as a professional cyclist.” We also spoke with Dr. Ginger Southall who actually used the tent before her successful climb of Denali in Alaska
From Cleats to Crampons Hypoxico has created a tent system that can simulate an environment up to 16,000 ft. Much like the altitude bed, the tent’s original intention was for use by elite athletes to train low and sleep high, a topic that ExplorersWeb has written about previously. Shaun got the idea to start using it for climbers after reading an account of the Everest tragedy of 1996, “It was after reading ‘Into Thin Air’ and about how the problems of lack of oxygen and people not being prepared properly that I realized how many lives can be saved and people helped if they can prepare before going.” Normobaric vs. Hypobaric Unlike the altitude bed, which is hypobaric, the tent system is normobaric. This means that the tent is able to acclimatize an individual without changing the pressure of the atmosphere they are in. While inside the tent, ears will not pop and the pressure level remains the same as that of the pressure outside the tent. The tent is made from nylon and other fabrics, while the bed has to be constructed of very strong plastics to withstand the immense pressure of depressurization. This difference makes the tent system lighter and more transportable than the bed. Because the bed would take 10 or 15 minutes to depressurize and to then re-pressurize, many users found themselves taking pee bottles into the chambers. The advantage of the bed is that not only does the prepare climber for altitude, but also how not to make a mess in a tent while in a snowstorm. Room for two The tent enables the user to enter and exit just like getting in and out of a camping tent. It also allows for couples to sleep together more comfortably - the altitude bed is a bit tight for two, and seeing how a spouse might potentially not see their husband/wife for a couple months while on expedition, the last few weeks together at home would be less friendlier if a spouse is forced to spoon with a hard Plexiglas cylinder. Instead of sucking air out to simulate altitude, the tent system pumps in air with a decreased level of oxygen. The air that is breathed at sea level is approximately 21% oxygen and the air pumped into the tent is only 14 or 15% oxygen. Nitrogen takes the place of the missing 6 or 7%. Previously, some attempted to do the same as the Hypoxic tent system, but did so by pumping in excess nitrogen. Hypoxico actually removes a portion of the oxygen before it pumps it on into the tent, which is more effective. There is also no concern about decompression sickness, ”we don’t change the pressure – the tent is completely safe, you can go in and out as you please without any risk of the bends or anything else.” In diving, excess nitrogen combined with pressure change results in life threatening illnesses. While the body is absorbing greater amounts of Nitrogen in the tent system, there is no threat of illness as the pressure of the environment is the same as sea level. Benefits By breathing in air with less oxygen, the body starts to create more red blood cells to more efficiently process the diminished oxygen level in the atmosphere. Effectively, the smaller tent can simulate an altitude of 16,000 ft, and the larger tent can simulate up to 12,000 ft. The systems have large clear windows, so it is not very claustrophobic and the device that removes the oxygen can do so with the ambient air – there are no pressurized canisters needed By and large the tent system is smaller, cheaper, lighter, and more convenient than the altitude bed. However, a big difference lies within the pressure difference. As the tent’s pressure is equivalent to sea level, it does not prepare the body to altitude the same as the hypobaric altitude bed does. The tent is meant to aid acclimatization, however, it will not prevent pulmonary or cerebral edema as effectively as the bed does. On Thursday, Dr. Ginger Southall's personal experience in the tent and on Denali... |