Symptoms and Signs of Altitude Sickness

Medical Author: John P. Cunha, DO, FACOEP
Medically Reviewed on 3/11/2019

Doctor's Notes on Altitude Sickness

Altitude sickness (also called mountain sickness) is an illness due to the decreasing amount of oxygen at high altitudes from about 4800 feet (1500 m) that may range from mild to even fatal at higher altitudes. Altitude sickness typically occurs when people travel from lower altitudes to higher altitudes (8000 feet or 2438 m or higher) in less than one day, but altitude sickness may occur at considerably lower altitudes depending on a person’s health. Altitude sickness is a general term that covers three major syndromes: acute mountain sickness (AMS), high-altitude pulmonary edema (HAPE), and high-altitude cerebral edema (HACE).

Early symptoms of altitude sickness include headache, fatigue, and insomnia. Other symptoms of altitude sickness may include dizziness, shortness of breath during exertion, nausea, and decreased appetite. If a person stays at high altitudes, late symptoms of altitude sickness include swelling of extremities and social withdrawal.

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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.