When exposed to air, which contains a lower proportion of oxygen component than normal, the human body begins to struggle with this fact. As a result, a number of physiological processes begin to take place. Short-term response includes faster vegetative functions, such as rapid breathing, increased heart rate, or blood mobilization from reservoirs. However, as a result of long-term exposure to hypoxia, the human body begins to adapt to those conditions.
In addition, long-term residence in high-altitude conditions triggers a variety of effects in the human body. The body will begin to produce increased amounts of the erythropoietin hormone (EPO). This will lead to an increase in the total number of red blood cells which have the ability to bind oxygen. It will facilitate a more efficient transport to important locations in the human body. An important effect of hypoxic exposure is the fact that the changes that occur in the body by prolonged exposure to hypoxia are long-term. They disappear only gradually. It takes several months for the body to return to the state before the hypoxic exposure.
Thanks to this fact, hypoxic systems are an invaluable tool for elite mountain climbers, as well. They can thus acclimatize to the high altitude before climbing the summit on ongoing basis, even in the comfort of their own home.
The second system, which can within a certain timeframe achieve the same effects as hypoxic training, is the hypoxic sleep. This method requires the use of a hypoxic tent. The advantage of hypoxic tents is based on the fact that athletes are training under normal conditions, which they are used to. They do not need to adapt their training to high-altitude conditions. They simply sleep in a hypoxic tent, while exposed to modified, hypoxic air. The gradual increase of simulated altitude at which the user is sleeping will force the body to undergo higher adaptation changes. Thanks to a hypoxic adapter it is possible that the athlete can enjoy a short nap up to an altitude of 6,400 meters above sea level.
Hypoxic sleep is very popular among athletes because, unlike training in hypoxic conditions, they do not have to undergo the difficult acclimatization to the given altitude. Therefore, they prefer "sleeping high, but training low."
Another important and latest method is hypoxia therapy (IHT). An indisputable advantage of this method is its practicality, as it is intended not only for athletes but for the general public, as well. Its main maxim is to promote health, treatment of lifestyle diseases, and overall rejuvenation of the human body.
During hypoxic therapy, arterial oxygen saturation decreases to a level that is not achievable by any other method. At this stage, adaptive changes at the mitochondrial level get under way. This enhances the production of mitochondrial enzymes, resulting in increasing of the body's ability to utilize oxygen and increasing the enzymatic antioxidant defences.
Hypoxic therapy has been vastly successful in many renowned medical facilities throughout Europe, especially in helping to treat civilization diseases.