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Acute Mountain Sickness
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.1
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.2 Ibuprofen and related drugs may help with headache.
Proposed Natural Treatments for Altitude Sickness
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 vitamin C, 400 IU of vitamin E, and 600 mg of lipoic acid daily) significantly improved symptoms of altitude sickness as compared to placebo.8 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.13
Three small, double-blind trials enrolling a total of about 100 people found preliminary evidence that use of the herb Ginkgo biloba can help prevent altitude sickness.3,9,14 However, a large scale double-blind study enrolling 614 people, failed to find benefit.10 (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.15 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.4 However, studies on this treatment have resulted in contradictory results.5,6,7
Magnesium, glutamine, and milk thistle, alone or in combination, have been suggested for altitude sickness, but there is no meaningful evidence that they work. The herb Rhodiola rosea has also been proposed as an altitude sickness treatment, but current evidence is more negative than positive.11 One study of the supplement arginine found that it increased elevation-related headaches.12
References[ + ]
1. Berkow R, Beers MH, Fletcher AJ, eds. Merck Manual of Medical Information. Home Edition. New York, NY: Pocket Books; 1997.
2. Coote JH. Medicine and mechanisms in altitude sickness. Recommendations. Sports Med. 1995;20:148-159.
3. Roncin JP, Schwartz F, D'Arbigny P. EGb 761 in control of acute mountain sickness and vascular reactivity to cold exposure. Aviat Space Environ Med. 1996;67:445-452.
4. Lawless NP, Dillard TA, Torrington KG, et al. Improvement in hypoxemia at 4600 meters of simulated altitude with carbohydrate ingestion. Aviat Space Environ Med. 1999;70:874-878.
5. Gray D, Milne D. Effect of dietary supplements on acute mountain sickness. Percept Mot Skills. 1986;63:873-874.
6. Lawless NP, Dillard TA, Torrington KG, et al. Improvement in hypoxemia at 4600 meters of simulated altitude with carbohydrate ingestion. Aviat Space Environ Med. 1999;70:874-878.
7. Swenson ER, MacDonald A, Vatheuer M, et al. Acute mountain sickness is not altered by a high carbohydrate diet nor associated with elevated circulating cytokines. Aviat Space Environ Med. 1997;68:499-503.
8. Mansoor JK, Morrissey BM, Walby WF et al. L-Arginine Supplementation Enhances Exhaled NO, Breath Condensate VEGF, and Headache at 4342 m. High Alt Med Biol. 2005;6:289-300.
9. Gertsch JH, Seto TB, Mor J, et al. Ginkgo biloba for the prevention of severe acute mountain sickness (AMS) starting one day before rapid ascent. High Alt Med Biol. 2002;3:29-37.
10. Gertsch JH, Basnyat B, Johnson EW, et al. Randomised, double blind, placebo controlled comparison of ginkgo biloba and acetazolamide for prevention of acute mountain sickness among Himalayan trekkers: the Prevention of High Altitude Illness Trial (PHAIT). BMJ. 2004 Mar 11. [Epub ahead of print]
11. Wing SL, Askew EW, Luetkemeier MJ, et al.. Lack of effect of Rhodiola or oxygenated water supplementation on hypoxemia and oxidative stress. Wilderness Environ Med. 2003;14:9-16.
12. Bailey DM, Davies B. Acute mountain sickness; prophylactic benefits of antioxidant vitamin supplementation at high altitude. High Alt Med Biol. 2001;2:21-29.
13. Subudhi AW, Jacobs KA, Hagobian TA et al. Changes in ventilatory threshold at high altitude: effect of antioxidants. Med Sci Sports Exerc. 2006;38:1425-1431.
14. Moraga FA, Flores A, Serra J, et al. Ginkgo biloba decreases acute mountain sickness in people ascending to high altitude at Ollague (3696 m) in Northern Chile. Wilderness Environ Med. 2007;18:251-257.
15. Chow T, Browne V, Heileson HL, et al. Ginkgo biloba and acetazolamide prophylaxis for acute mountain sickness: a randomized, placebo-controlled trial. Arch Intern Med. 2005;165:296-301.
Last reviewed December 2015 by EBSCO CAM Review Board
Last Updated: 12/15/2015
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