Acute mountain sickness is a set of symptoms caused by the lower pressure and reduced amount of oxygen at high altitudes (above 7,000 feet). The symptoms are headache, dizziness, shortness of breath, fatigue, and nausea, or, in serious cases, extreme fatigue, impaired motor control, and fluid accumulation in the brain and lungs. In general, the greater the altitude and the more rapid the ascent, the greater the likelihood of severe symptoms. Many deaths on Mt. Everest and other high mountains can be attributed to the effects of altitude sickness. However, in most cases, altitude sickness is a benign condition that afflicts people from sea level when they go on a ski vacation or hiking in the mountains.
The best treatment for altitude sickness is prevention. Individuals planning an ascent of high mountains such as Mt. Everest should take as much time as possible to acclimate to the starting elevation. Keep in mind that full adjustment to the reduced oxygen content of the air may take several weeks. In general, ascents should be gradual. One recommendation suggests 2 days for an 8,000-foot elevation gain plus 1 day for each 1,000 to 2,000 feet afterwards.
However, such recommendations are not practical for people who fly to a vacation destination, such as a ski resort, and must deal with the effects of reduced oxygen all at once. To prevent or treat mild cases of altitude sickness, you should drink plenty of water and avoid alcohol, caffeine, and salty foods. If severe symptoms develop, the best response is to descend as rapidly as possible.
Conventional treatments include acetazolamide or dexamethasone for prevention or treatment of mild altitude sickness, and nifedipine for people prone to pulmonary edema.
Ibuprofen and related drugs may help with headache.
A double-blind trial of 18 mountaineers climbing to the Mt. Everest base camp found that use of an antioxidant vitamin supplement (providing 1,000 mg of
, 400 IU of
, and 600 mg of
daily) significantly improved symptoms of altitude sickness as compared to placebo.
Treatment was begun 3 weeks prior to ascent and continued during the 10 days of climbing. However, this was a very small study, and its results cannot be taken as reliable.
Another small study using similar antioxidants in a similar manner found that use of antioxidants might offer benefits in the first couple of days of high altitude ascent, but that these benefits decline with acclimatisation.
Three small, double-blind trials enrolling a total of about 100 people found preliminary evidence that use of the herb
can help prevent altitude sickness.
However, a large scale double-blind study enrolling 614 people, failed to find benefit.
(The drug acetazolamide, however, did provide significant benefits compared to placebo.) A similarly designed smaller study, enrolling 57 people, also failed to find ginkgo effective.
Overall, the balance of evidence suggests that ginkgo is not effective for this purpose.
High-carbohydrate meals are sometimes recommended for preventing altitude sickness. The reasoning is that carbohydrate ingestion increases carbon dioxide production, which in turn stimulates an increased rate of breathing.
However, studies on this treatment have resulted in contradictory results.
, alone or in combination, have been suggested for altitude sickness, but there is no meaningful evidence that they work. The herb
has also been proposed as an altitude sickness treatment, but current evidence is more negative than positive.
One study of the supplement
found that it