Higher Altitude's Effects on Breathing

High altitude of 5,000 feet and above is characterized by an increase in barometric pressure, which adversely affects breathing. The effects of high altitude on breathing can cause serious, potentially life-threatening illnesses. Altitude illness stems from low levels of oxygen and carbon dioxide present in the blood due to a reduction in oxygen intake and an increase in the amount of carbon dioxide expelled. The symptoms include headache, nausea, weakness and confusion. Avoiding rapid ascent and allowing the body time to acclimatize will help to normalize breathing and prevent the physiological effects that lead to altitude sickness.

Hypoxia

• High altitude makes breathing less effective and results in hypoxia, a condition resulting from oxygen deprivation. At high altitudes, barometric pressure increases, and while oxygen saturation in the atmosphere remains at the average of 21 percent, each breath we take contains fewer molecules of oxygen. This lower intake of oxygen results in weakness and fatigue with normal physical activity. Prolonged hypoxia starves cells of the oxygen and can damage multi-organ systems, such as the central nervous system, and even cause these organs to fail.

Hyperventilation

• When the brain becomes aware of hypoxia in the blood, it reacts with hyperventilation, or rapid, deep breathing, which causes the lungs to expel more carbon dioxide than normal. The brain signals breathing based on a normally high level of carbon dioxide present in the blood. If levels drop, the brain will not trigger the lungs to breath. This means that we must make the conscious decision to breathe. Unresolved hyperventilation can cause light-headedness, dizziness, confusion and stroke.

Dyspnea

• Dyspnea, or shortness of breath, can be caused by the panic of hyperventilation. In an effort to quickly take in air, breathing may be shortened so that the lungs are not filled to capacity during inhalation. This creates a feeling of being unable to breathe or of suffocating, which increases anxiety and prolongs hyperventilation. Lower volumes of air results in less oxygen being taken in and absorbed, contributing to lower oxygen levels in the blood.

Periodic Breathing

• The inability to control breathing caused by hyperventilation triggers periodic breathing, the odd breathing patterns that develop during sleep, which is characterized by cycles of erratic breathing. During a period of normal breathing, our respiration rate begins to slow gradually. This period is replaced by 10 to 15 seconds of holding our breath. The last step in the cycle is a recovery period of accelerated breathing. Periodic breathing can cause anxiety if the person wakes during the last two stages, either "not breathing" or "gasping for air."