Talk:Altitude sickness

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Over the long term, living at high altitude can cause secondary Polycythemia

My understanding is that the production of additional red blood cells is a normal part of acclimatization. Is this considered polycythemia, or does it only become polycythemia when one produces more than one needs? uFu 04:14, 28 June 2006 (UTC)
Technically, it appears so. Being at high altitude causes physiologic polycythemia. See the polycythemia article for more. --Mdwyer 05:50, 2 February 2007 (UTC)


why not write 2500 m?

When you reach about 3000 m the air gets thin holding less percentige of are oxygen making the body breath faster once this has happened, a body not used to the thin air would start to shut down causing altitude sickness —The preceding unsigned comment was added by 210.8.213.138 (talkcontribs). 01:33, 31 July 2006



This article should probably not point from acclimitization... Open water swimmers acclimitize to progressively cooler tempereratures as part of their training. 192.75.95.127 02:02, 6 February 2007 (UTC)

"acclimitization" is a typo, now points at acclimatization hike395 03:51, 6 February 2007 (UTC)

AMS vs. Dehydration[edit]

Someone had {{fact}} tagged the statement that drinking plenty of water could reduce the occurrence of AMS on the grounds that the extra water simply treated dehydration and not actually AMS. As one who has a background in emergency medicine including high altitude medicine, I can tell you that, although that is true to a point and many of the effects of AMS are caused by decreased levels of hydration, it is just not that simple. When a person travels to any environment where the atmospheric partial pressure of oxygen is less than that present at sea level, the body compensates in various ways including an increase in respiratory rate and depth creating an overall increase in minute volume. This has the consequence of increasing the rate of moisture loss through the lungs as that rate is directly linked to minute volume. This, of course, requires an increase in water consumption in order to compensate and maintain homeostasis. The total situation is, however, more complex that that. As a further result of the incresed minute volume, more CO2 is expelled from the body. CO2 is mildly acidic and serves to balance the pH level of the blood. With more CO2 being expelled, the blood pH rises causing a mild alkalosis. To compensate for this increase in pH, the kidneys respond by removing bicarbonate ions (moderately alkaline) from the blood and excreting them with the urine. This, in turn, increases urine output further reducing the body's overall level of hydration. As a result, a dramatic increase in water consumption is essential at high altitudes to maintain health. Though, admittedly, it is technically correct to simply call this whole process dehydration, it is dehydration secondary to AMS and is considered as such in medical studies of the effects of altitude. Thus, increased water consumption should be viewed as a means of prevention/treatment of AMS as the two are inextricably linked. Normally, I could back all that up with references to medical books, however, I am on the road at the moment and away from my medical library. For now, I have grabbed one of several references I found on Google books and added it as a stop-gap measure. I can add a better reference in a couple of weeks when I'm back home. At that point I will also add some of the information I stated above to the article once I can source it properly. I hope that clears up the confusion. OlenWhitakertalk to me or don't • ♣ 21:10, 2 May 2008 (UTC)


While very helpful, I noticed this article suggests that aircraft travel does not cause Altitude Sickness because of the pressurisation of modern aircraft. My understanding is that most jets pressurise aircraft cabins to an air pressure equivalent to being at about 7,500 feet above sea level. This is a height at which Altitude Sickness can occur, according to this article. I suspect that the key point is possibly the period of exposure to this lower effective air pressure - that air travel is too quick to cause Alt. Sickness. cheers, John, brisbane Australia 60.240.254.133 (talk) 12:44, 17 June 2008 (UTC)

– The full explanation for aircraft travel and AMS should involve both air pressure and position : lung function always decreases as you lie down.Thus the importance of sleeping altitudes.· Vistet (talk) 21:53, 27 July 2008 (UTC)

myo-inositol trispyrophosphate(ITPP) could possibly be useful in treating altitude sickness Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0812381106) —Preceding unsigned comment added by 120.16.150.228 (talk) 10:56, 7 March 2009 (UTC)

There is a very polished study from the NEJM in 2007 demonstrating that a suprising number of people get AMS symptoms on aircraft. I have cited it in the article. Empyema (talk) 21:34, 23 December 2009 (UTC)


Severe Cases Mismatch[edit]

The last paragraph, beginning with "A person suffering from serious symptoms of altitude sickness..." is totally inappropriate. Those describe the Time of Useful Consciousness as arrived at by rapid decompression, a condition in which the cabin pressurization in an aircraft is lost due to a failure of the pressurization system or failure in the integrity of the pressurized compartment, or of a failure in the oxygen supply of an unpressurized aircraft at those altitudes. It does NOT represent the time "a person suffering from serious symptoms of altitude sickness has in which corrective action can be taken," and should be striken from the article. People suffering from AMS, HAPE, and HACE can, and have been, assisted off mountains over several hours, with their symptoms improving as they descend. The key thing to remember when symptoms present is to immediately 1) stop ascending, 2) start descending, 3) get medical treatment without delay.

  • Agree. I have deleted the section. Confuses AMS with hypoxia. For the record the removed section read:

A person suffering from serious symptoms of altitude sickness has a relatively short period of time of useful consciousness in which corrective action can be taken. The following is a correlation of approximate altitude to the amount of time that a person will have useful consciousness:[citation needed]* 20,000 ft / 6,100 m = 5-12 minutes (peak of Mount McKinley or Mount Kilimanjaro)

  • 25,000 ft / 7,620 m = 3-5 minutes;
  • 29,000 ft / 8,840 m = 1-2 minutes; (peak of Mount Everest)
  • 40,000 ft / 12,200 m = 9-15 seconds (represents the oxygen that was in a person's system before the exposure)

Ex nihil (talk) 02:32, 8 April 2010 (UTC)

Other methods[edit]

I've removed the sentence "There are also canned oxygen products that are a portable alternative<ref>http://www.oxygenpod.com</ref>." on the grounds that it is speculative nonsense. The website of the portable alternative cited states that it contains "2 liters of 95% oxygen and 5% nitrogen ... and lasts a full 40 breaths"[1]. Two litres is about a single breath and isn't going to make any impression on AMS. In addition, that website cautions that it "is for recreational use only, and is not a medical device. It should not be used to treat or cure any medical condition"[2]. If any reliable sources can be found that show "canned oxygen products that are a portable alternative" can be used for prevention of altitude sickness, I'd be happy to see the sentence replaced including a proper source. --RexxS (talk) 03:10, 6 February 2010 (UTC)

Medical treatment[edit]

It would be nice to find a good secondary source, a review in a quality journal, for this section to try to reflect the weight of mainstream medical opinion per WP:MEDRS, but I haven't found one yet. At present most of the sources are primary, and we don't have an overview. I'll put a more recent primary study on the effects of ginkgo biloba and acetazolamide here. Perhaps other editors can add potential sources below, with a view to bringing the section up to date. --RexxS (talk) 15:41, 22 April 2010 (UTC)

Potential sources[edit]

The percentage of oxygen in air, at 21%, remains almost unchanged up to 7,000 feet (2,100 m)[edit]

Does it change? If so, how? Moletrouser (talk) 23:29, 11 October 2010 (UTC)

Since the molecules of oxygen and the molecules of nitrogen are similar in their physical properties, there's very little effect on the ratio of O2/N2 as altitude increases. However, air also contains around 1% argon and a variable small percentage of water vapour. These molecules are sufficiently different from the O2+N2 mixture to produce a very small change in the relative fractions of gases at altitude. Some idea of the size of the difference can be seen from observing that dry air contains about 20.9% oxygen, while air at around 50% relative humidity contains about 20.8% oxygen. To be honest, that sentence is actually over-conservative, and not particularly relevant to altitude sickness. The change in the fraction of oxygen at altitude is negligible compared to even minor local variations in air pressure, when calculating the partial pressure of oxygen at a given height. The principal variation with altitude is the density of air, and we can calculate that without problem. There's a (non-RS) page at http://wahiduddin.net/calc/density_altitude.htm that links to several calculators, if you're interested in actual figures. --RexxS (talk) 00:25, 12 October 2010 (UTC)


No mention of decompression[edit]

this article identifies lack of oxygen as the main reason for the altitude sickness, but can't fast decompression causing dilatation in the soft tissues be considered as a cause of the pains too?

Having travelled by plane from Lima to Cuzco, I had noticed on my arrival that bottles of water and snack packs were inflated due to the lower pressure. Isn't there something similar occuring in the blood vessels and circulatory system that could explain the acute headaches? — Preceding unsigned comment added by 92.160.176.74 (talk) 05:26, 3 September 2011 (UTC)

Solids and liquids are pretty much incompressible, so any physical effect of a change in pressure is only likely to come about where gases are involved. The air inside the bottles of water and snack packs would indeed tend to expand as the ambient air pressure is reduced. Those are sealed containers, though, and you wouldn't expect to see such an effect if you left the top on the bottle loose. Similarly, the human body is capable of eliminating trapped or dissolved gases under normal conditions as ambient pressure changes. You are right that fast decompression often produces conditions where the body cannot bring trapped or dissolved gases into equilibrium fast enough to avoid pressure effects – see our articles on Decompression sickness, Arterial gas embolism and Barodontalgia for examples of where this can occur. Nevertheless, climbing up a mountain is not realistically going to happen quickly enough to produce these sort of effects, so acute mountain sickness is very unlikely to have a cause from the inflation of gases within the body. I would suggest that the effects of lack of oxygen and dehydration are sufficient to explain the syndrome. The article on decompression sickness attempts to examine the decompression problems associated with high-altitude flying and spacewalks, and perhaps it should be linked from here if you feel the two conditions are sufficiently similar to warrant it? --RexxS (talk) 01:39, 4 September 2011 (UTC)

Long term variation in susceptibility?[edit]

Have any studies shown whether there is natural long term variation in susceptibility to altitude sickness and whether repeated short term acclimatization can build up longer term resistance? It would be interesting to see this covered in the article. Greenshed (talk) 22:38, 30 March 2014 (UTC)