উচ্চতা (উল্লম্ব দূরত্ব): সংশোধিত সংস্করণের মধ্যে পার্থক্য

Medicine recognizes that altitudes above {{convert|1500|m|ft}} start to affect humans,<ref>{{cite web|title=Non-Physician Altitude Tutorial |publisher=International Society for Mountain Medicine |url=http://www.ismmed.org/np_altitude_tutorial.htm |accessdate=22 December 2005 |archiveurl=https://web.archive.org/web/20051223065508/http://www.ismmed.org/np_altitude_tutorial.htm |archivedate=23 December 2005 |url-status=dead }}</ref> and there is no record of humans living at extreme altitudes above {{convert|5500|-|6000|m|ft}} for more than two years.<ref name=highestHabitation>{{cite journal|last=West|first=JB|pmid=12631426|title=Highest permanent human habitation|journal=High Altitude Medical Biology|volume=3|pages=401–407|year=2002|doi=10.1089/15270290260512882|issue=4}}</ref> As the altitude increases, atmospheric pressure decreases, which affects humans by reducing the [[partial pressure]] of [[oxygen]].<ref name=pubmed>{{cite journal|title=Oxygen at high altitude|journal=British Medical Journal|first=Andrew J|last=Peacock|date=17 October 1998|volume=317|pages=1063–1066|pmid=9774298|issue=7165|pmc=1114067|doi=10.1136/bmj.317.7165.1063}}</ref> The lack of oxygen above {{convert|8000|ft|m|order=flip}} can cause serious illnesses such as [[altitude sickness]], [[high altitude pulmonary edema]], and [[high altitude cerebral edema]].<ref name=MedicalProblems>{{cite journal |last1=Cymerman|first=A|last2=Rock|first2=PB |title=Medical Problems in High Mountain Environments. A Handbook for Medical Officers |publisher=U.S. Army Research Inst. of Environmental Medicine Thermal and Mountain Medicine Division Technical Report |volume=USARIEM-TN94-2 |url=http://archive.rubicon-foundation.org/7976|year=1994}}</ref> The higher the altitude, the more likely are serious effects.<ref name=MedicalProblems/> The human body can [[altitude acclimatization|adapt to high altitude]] by breathing faster, having a higher heart rate, and adjusting its blood chemistry.<ref name=BordenHuman>{{cite book |last1=Young |first1=Andrew J. |last2=Reeves |first2=John T. |title=Human Adaptation to High Terrestrial Altitude. In: Medical Aspects of Harsh Environments |volume=2 |chapter=21 |location=Borden Institute, Washington, DC |year=2002 |chapter-url=http://www.bordeninstitute.army.mil/published_volumes/harshEnv2/harshEnv2.html | archiveurl= https://web.archive.org/web/20090111214536/http://www.bordeninstitute.army.mil/published_volumes/harshEnv2/harshEnv2.html| |archivedate=১১ 11জানুয়ারি January 2009২০০৯ | url-status=অকার্যকর |সংগ্রহের-তারিখ=২ সেপ্টেম্বর ২০২০ live}}</ref><ref name=Acclimatization>{{cite journal |last1=Muza|first1=SR|last2=Fulco|first2=CS|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 |accessdate=5 March 2009 }}</ref> It can take days or weeks to adapt to high altitude. However, above {{convert|8000|m|ft|-3}}, (in the "[[death zone]]"), altitude acclimatization becomes impossible.<ref name="PBS">{{cite web|url= https://www.pbs.org/wgbh/nova/transcripts/2506everest.html|title= Everest:The Death Zone|work= Nova|publisher= PBS|date= 24 February 1998}}</ref>