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| Feb 13, 2014
Written By Jordan Guillot, ACSM Health Fitness Specialist
Varying altitudes may propose a new challenge for athletes competing in the Winter Olympic Games. As the elevation above sea level increases, not only does the barometric pressure of the air decrease, but the pressure of oxygen in that air also decreases (Exercise Physiology, McArdle, Katch, and Katch, 6th ed., 2007).
This decrease in pressure of oxygen becomes that new challenge. The diffusion of oxygen from inspired air in the lungs across a membrane and into the blood stream depends on a pressure gradient (from area of higher pressure to area of lower pressure). As blood flows through the body, muscles and other tissues utilize the oxygen, which decreases the pressure of oxygen in the blood stream before returning to the heart. Once this blood reaches the lungs from the heart, its pressure of oxygen is much less than that of the inspired air.
This difference in pressure allows diffusion of oxygen from the greater pressure inside the lungs and into the area of lower pressure – the blood stream – to be delivered throughout the body. The blood leaving the lungs is what is commonly known as the oxygenated blood, and is vital to muscle and tissue function. At higher altitudes, as mentioned before, the pressure of oxygen is lower than at sea level, and that pressure continues to decrease with every increase in elevation. If the pressure of oxygen lowers in inspired air, the difference in pressures between the inspired air and the blood stream would decrease, also. This decrease in difference lowers the rate at which diffusion takes place. Thus, a decrease in oxygen saturation of the blood can be expected. Now the muscles have an inadequate supply of oxygen, which inevitably affects and decreases performance than what can be expected at sea level or at lower altitudes.
Olympic Winter Games rules state that a downhill skiing course must have a vertical drop of 800-1100 meters (2600-3280 ft.) (FIS Ski Rules 2008, 79). This is more than enough vertical distance for the start and finish to differentiate in their pressures of oxygen. However, there is a question of how much oxygen pressure change effects might come into play. Given these events are relatively brief and as a consequence, is a substantial part of the needed energy generated by anaerobic pathways?