Editing Altitude sickness (section)

=== Altitude acclimatization ===<!-- This section is linked from [[Mount Kilimanjaro]] -->
Altitude acclimatization is the process of adjusting to decreasing [[oxygen]] levels at higher elevations, in order to avoid altitude sickness.<ref name=Acclimatization>{{Cite journal |last1=Muza |first1=S.R. |last2=Fulco |first2=C.S. |last3=Cymerman |first3=A. |title=Altitude Acclimatization Guide |journal=U.S. Army Research Inst. Of Environmental Medicine Thermal and Mountain Medicine Division Technical Report |issue=USARIEM–TN–04–05 |year=2004 |url=http://archive.rubicon-foundation.org/7616 |access-date=5 March 2009 |archive-url=https://web.archive.org/web/20090423042451/http://archive.rubicon-foundation.org/7616 |archive-date=23 April 2009 |url-status=usurped}}</ref> Once above approximately {{convert|3000|m|-3}}{{snd}}a pressure of {{convert|70|kPa|atm}}{{snd}}most climbers and high-altitude trekkers take the "climb-high, sleep-low" approach. For high-altitude climbers, a typical acclimatization regimen might be to stay a few days at a [[base camp]], climb up to a higher camp (slowly), and then return to base camp. A subsequent climb to the higher camp then includes an overnight stay. This process is then repeated a few times, each time extending the time spent at higher altitudes to let the body adjust to the oxygen level there, a process that involves the production of additional [[Homeostasis#Blood oxygen content|red blood cells]].<ref name=tortora>{{cite book |vauthors=Tortora GJ, Anagnostakos NP |title=Principles of anatomy and physiology |url=https://archive.org/details/principlesofanat05tort |url-access=registration |pages=[https://archive.org/details/principlesofanat05tort/page/444 444]–445|edition= Fifth |location=New York |publisher=Harper & Row, Publishers |date=1987 |isbn=978-0-06-350729-6}}</ref> Once the climber has acclimatized to a given altitude, the process is repeated with camps placed at progressively higher elevations. The rule of thumb is to ascend no more than {{convert|300|m|-2|abbr=on}} per day to sleep. That is, one can climb from {{convert|3000|m|abbr=on}} ({{convert|70|kPa|atm|abbr=on|disp=or}}) to {{convert|4500|m|-3|abbr=on}} ({{convert|58|kPa|atm|abbr=on|disp=or}}) in one day, but one should then descend back to {{convert|3300|m|abbr=on}} ({{convert|67.5|kPa|atm|abbr=on|disp=or}}) to sleep. This process cannot safely be rushed, and this is why climbers need to spend days (or even weeks at times) acclimatizing before attempting to climb a high peak. Simulated altitude equipment such as [[altitude tent]]s provide hypoxic (reduced oxygen) air, and are designed to allow partial pre-acclimation to high altitude, reducing the total time required on the mountain itself.

Altitude acclimatization is necessary for some people who move rapidly from lower altitudes to higher altitudes.<ref>{{Cite web |url=http://www.altitudemedicine.org/altitude-illness/ |title=Altitude Illness |publisher=[[Institute for Altitude Medicine]] |location=Telluride, Colorado}}</ref>