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How a CAT System Works

Regardless of elevation, the air we breathe contains 20.9% oxygen, 78% nitrogen, and 1% trace gases (carbon dioxide and argon). Because these are relative amounts this composition is true both at sea level and at the top of Mt Everest. Why then, do people talk about the air being thinner at high altitudes, or claim that there is less oxygen at high altitudes? The answer is because in an absolute sense there is less air at higher altitudes.

As barometric pressure decreases with increasing elevation, the number of molecules in a given volume of air decreases proportionately. The result, on an absolute basis, is that there are fewer oxygen molecules present in air at higher elevations. What is changing is the actual number of air molecules in a given volume of air, or the air density. This in turn means that there are fewer oxygen molecules available to be transferred to the bloodstream in the lungs. The absolute number of nitrogen molecules also decreases at the same rate, so that the relative proportions of oxygen molecules in the air remains constant at 21% even though there are less molecules of oxygen in the air at high altitudes.

CAT's systems simulate high altitude environments regardless of the elevation at which they are used. This simulation is accomplished using a high-flow hypoxic air delivery unit and a semi-sealed enclosure. The air unit draws in ambient room air and separates the oxygen molecules from the nitrogen molecules, creating the hypoxic or oxygen reduced air. This separation is done in a special filter called a molecular sieve bed.

Molecular sieve beds are chambers filled with a naturally occurring tetrahedral substance called zeolite. When air is passed through a sieve bed under pressure, the oxygen molecules are trapped in the zeolite, while the nitrogen molecules are allowed to pass through. This trapped oxygen is exhausted while the hypoxic air is pumped into the semi-sealed enclosure to create the environment where there is less relative and absolute oxygen. Simulated altitudes of 14,500 feet can be achieved, and can be controlled to within 100 feet accuracy using CAT's proprietary digital control system.

The second major component of the CAT system is the hypoxic enclosure itself. The enclosure receives the hypoxic air from the air unit and contains it within a semi-sealed space. Hypoxic air is continuously pumped into the enclosure at rates as high as 150 liters/minute to maintain the hypoxic environment. Because of the high flow through rates, carbon dioxide, heat, and humidity diffuse from the tent creating a comfortable environment within the enclosure. These features allow CAT to offer the largest enclosures in the industry allowing the greatest convenience and comfort.