Backpacker's Anonymous - Altitude Sickness

Altitude Sickness

Altitude Sickness
Altitude sickness is caused by reduced oxygen pressure in thin mountain air developing in individuals' rapid ascent above 5000 feet in elevation. Altitude sickness can effect anyone, regardless of age or physical condition and generally manifests in the form of Acute Mountain Sickness though two more critical conditions (high-altitude pulmonary edema and high-altitude cerebral edema) may develop.

Acute Mountain Sickness
Acute Mountain Sickness (AMS) is a mild form of altitude sickness which effects nearly 20 percent of all people ascending higher than 8000 feet above sea level in less than one day but can occur as low as 5000 feet. The symptoms are headache, shortness of breath, nausea, vomiting and insomnia. Symptoms of AMS may begin within hours after ascent but usually disappear within 24-48 hours as the body acclimatizes to the reduced oxygen pressure.

Prevention of AMS
Before your hike

Maintain a good work/rest cycle. (Physical conditioning at lower elevations is no guarantee of protection.)

Avoid alcohol, sleeping pills or narcotics. They may decrease ventilation, intensify hypoxemia and make symptoms worse.

Spend your first night at or below 7000 feet.

Diamox (acetazolamide) may be taken one to two days prior to departure.

During the hike

Drink plenty of fluids.

Eat high-carbohydrate foods (rice, pasta, etc.). Avoid fatty and extra salty food.

Pace yourself, especially in the first 24 hours. Take it slow and give your body time to adjust.

Change elevation in stages. Ascending more than 2000 feet in a day above 7000 feet should be fine as long as you don't sleep more than 2000 feet higher than you did the night before.

Treatment of AMS

Headaches can be treated with ibuprofin or aspirin.

Diamox may be taken twice a day for prevention and treatment of AMS. Diamox is especially helpful with the insomnia and other symptoms of AMS

Descend. If symptoms persist, there is no substitution for descending to lower elevations.

High-Altitude Pulmonary Edema*
Symptoms characterizing high-altitude pulmonary edema (HAPE) include those of AMS but are compounded with strong coughing that produces a frothy, sometimes blood-tinged, sputum.

High-Altitude Cerebral Edema*
Symptoms characterizing high-altitude cerebral edema (HACE) include those of AMS but are compounded with staggering, confusion, and hallucination.

*Both HAPE and HACE are more serious conditions than AMS, usually developing after one to four days above about 9000 ft. Both conditions are serious and require professional medical attention.

The information provided here is for informational purposes only and is not intended to be an exhaustive resource for the sport of backpacking. Before beginning any backpacking trip, consult the professionals at your local outdoor outfitter. By reading the information provided above, the user agrees not to hold the author of the information or the hosting service of the information liable for loss of any kind as a result of its use.