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How Does Going From Sea Level to Higher Elevations Affect Our Ability to Breathe?

Oxygen is a vital component to survival and humans must constantly bring in more oxygen from the atmosphere through breathing. The air we breathe is approximately 21 percent oxygen; this is true whether we are at sea level or higher elevations. The main difference is that the amount of all molecules, including oxygen molecules, present at high elevations is much lower than at sea level. Less oxygen makes it more difficult to breath, which can lead to altitude sickness and even death.

Air Pressure
- Air pressure, which is a measurement of the weight of the air pressing down on an object, changes as elevation levels change. For example, at sea level, air pressure is equal to 10 meters of water pressing down on you. As a person progresses into higher elevations, the amount of atmosphere available to press down on an individual decreases. With this decrease in pressure, this means there is less air available for an individual to breathe.
Oxygen Saturation
- One vital measurement of how much oxygen a person is receiving to vital organs, including the heart and brain, is the oxygen saturation of the blood, or SaO2 level. At sea level, with a healthy person breathing normally, the SaO2 should be around 98 percent. At 2,000 feet in elevation, this same individual would see their SaO2 levels drop slightly to 97 percent. At 8,000 feet, this person's SaO2 level would reach just 91 percent. Each decrease, while small, may have a significant impact on organ functions.
Altitude Sickness
- Altitude sickness occurs in some individuals when moving quickly from areas of low elevation to high elevation. This sickness is due to the change in air pressure. Common symptoms include severe headaches, lack of appetite, vomiting, weakness, laziness, dizziness and the inability to sleep. Altitude sickness can lead to death in rare cases. Cures for altitude sickness include retreating to lower altitudes, acclimating to the higher elevations gradually and using supplemental oxygen to breathe.
Athletes
- The body creates more red blood cells to accommodate for the lack of oxygen present at higher elevations. More red bloods cells can more effectively capture oxygen that is present. Athletes, especially distance athletes such as runners and swimmers, use this process to their advantage. The athlete will train at high altitudes to produce more red blood cells and compete at lower altitudes. These additional red blood cells transport oxygen from the atmosphere to the muscles and heart to increase performance.

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