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Cause: Altitude sickness occurs when a person is not used to low oxygen levels at high altitudes (above 6,000-8,000 ft or 1,829-2,438 m). Although human bodies can adjust to changes in altitude, the process takes time.
Travel by plane, car or bus and even hiking may not give you enough time to adjust, and you may develop altitude sickness.
Acute mountain sickness (AMS) can develop within hours after ascending to a higher altitude. Symptoms may include headache, insomnia, irritability, dizziness, muscle aches, fatigue, loss of appetite, nausea, vomiting, and swelling of the face, hands and feet.
Severe forms of altitude sickness are high altitude cerebral edema (HACE) and high altitude pulmonary edema (HAPE). Danger signs of severe altitude sickness include severe headache, extreme fatigue or breathlessness (especially while resting), and any neurological problems such as stumbling, confusion, poor judgment or changes in consciousness.
For AMS symptoms, limit your activity level and remain at the same altitude for a day or two before resuming your climb. Aspirin or ibuprofen may be used for headache. Drink plenty of water. If symptoms worsen during a day of rest, descend until you improve.
HACE and HAPE are medical emergencies and may result in coma or even death. It is crucial to descend and receive drug and oxygen therapy as soon as possible.
The key to prevention is to ascend slowly and include rest days at intermediate altitudes.
Drink plenty of water. Avoid alcohol and unnecessary medications because the effects may be increased at high altitude.
Avoid drugs that decrease breathing rate (such as sleeping pills, tranquilizers and narcotic based pain relievers). A diet high in carbohydrates may be beneficial.
Avoid overexertion during the first few days at a high altitude.
To avoid severe illness and death, keep in mind three rules:
- Learn the early symptoms of altitude sickness and be willing to admit that you have them.
- If you experience symptoms of altitude sickness, no matter how minor they seem, never ascend and sleep at a higher altitude.
- Descend if symptoms become worse while resting at the same altitude.
If you have heart or lung problems, plan to go to extremely high altitude or have had altitude sickness in the past, consult a clinician for prevention and treatment options.
People who have experienced HACE or HAPE should avoid returning to high altitudes.
Acetazolamide (Diamox), available by prescription, can prevent altitude sickness if taken before ascent. It increases breathing rate and speeds adjustment. Side effects may include increased urination and tingling in fingers, toes and sometimes around the mouth, which are not reasons to stop medication. People allergic to sulfa should not take Diamox.