Altitude sickness

Altitude sickness, also known as acute mountain sickness (AMS), is a pathological effect of high altitude on humans, caused by acute exposure to low partial pressure of oxygen at high altitude. It commonly occurs above 2,400 meters (approximately 8,000 feet). Early symptoms are headache, fatigue, shortness of breath, nausea, and sleep disturbances. Severe symptoms include pulmonary edema (fluid in the lungs) and cerebral edema (swelling of the brain).

Causes

Altitude sickness is caused by reduced air pressure and lower oxygen levels at high altitudes. The faster you climb to a high altitude, the more likely you will get acute mountain sickness. You can also get it if you go to a high altitude and exercise (like skiing, hiking, or biking) before your body has adjusted to the altitude.

Symptoms

Symptoms of altitude sickness usually appear within hours of moving to higher altitudes. They vary depending on the speed of your climb and how hard you push (exert) yourself. Symptoms usually come on within 12 to 24 hours of reaching a higher elevation and then get better within a day or two as your body adjusts to the change in altitude.

Prevention

Prevention of altitude sickness includes acclimatization, the process of gradually adjusting to changes in environment, such as altitude. It is recommended to ascend no more than 1,000 feet per day to sleep, as the body makes adjustments during sleep to the higher altitude.

Treatment

Treatment of altitude sickness includes rest, hydration, and descending to a lower altitude as quickly and safely as possible. Medications such as acetazolamide and dexamethasone can also be used to help prevent and treat high altitude sickness.

See also

• High altitude pulmonary edema
• High altitude cerebral edema
• Acclimatization
• Hypoxia (medical)