Editing Hypothermia (section)

==Pathophysiology==
{{HumanTemperature}}
Heat is primarily generated in muscle tissue, including the heart, and in the liver, while it is lost through the skin (90%) and lungs (10%). Heat production may be increased (to over 1200 W in trained endurance athletes)<ref>{{cite journal | url=https://journals.humankinetics.com/previewpdf/view/journals/ijatt/1/4/article-p13.xml | title=Article Page 13 | journal=IJATT }}</ref> through muscle contractions (i.e. exercise and shivering). The rate of heat loss is determined, as with any object, by [[convection]], [[Conduction (heat)|conduction]], and [[radiation]].<ref name="Care 1999"/> The rates of these can be affected by [[body mass index]], body [[surface area]] to [[volume]] ratios, clothing and other environmental conditions.<ref name="Nuckton TJ 2000">{{cite journal |vauthors=Nuckton TJ, Claman DM, Goldreich D, Wendt FC, Nuckton JG | title=Hypothermia and afterdrop following open water swimming: the Alcatraz/San Francisco Swim Study | journal=American Journal of Emergency Medicine | volume=18 | issue=6 | pages=703–7 | date=October 2000 | pmid=11043627 | doi=10.1053/ajem.2000.16313}}</ref>

Many changes to physiology occur as body temperatures decrease. These occur in the cardiovascular system leading to the [[Osborn wave|Osborn J wave]] and other dysrhythmias, decreased [[central nervous system]] electrical activity, [[diuresis#Cold-induced diuresis|cold diuresis]], and [[Pulmonary edema#Noncardiogenic|non-cardiogenic pulmonary edema]].<ref>{{cite book |title=Rosen's emergency medicine: concepts and clinical practice 7th edition |last=Marx |first=John | name-list-style=vanc |year=2010 |publisher=Mosby/Elsevier|location=Philadelphia, PA |isbn=978-0-323-05472-0 |pages=1869–1870 }}</ref>

Research has shown that [[glomerular filtration rate]]s (GFR) decrease as a result of hypothermia.<ref>{{cite journal |vauthors=Broman M, Källskog O | title=The effects of hypothermia on renal function and haemodynamics in the rat | journal=Acta Physiologica Scandinavica | volume=153 | issue=2 | pages=179–184 | year=1995 | pmid=7778458 | doi=10.1111/j.1748-1716.1995.tb09849.x }}</ref> In essence, hypothermia increases preglomerular [[vasoconstriction]], thus decreasing both renal blood flow (RBF) and GFR.<ref>{{cite journal |vauthors=Broman M, Källskog O, Kopp UC, Wolgast M | title=Influence of the sympathetic nervous system on renal function during hypothermia | journal=Acta Physiologica Scandinavica | volume=163 | issue=3 | pages=241–249 | year=1998 | pmid=9715736 | doi=10.1046/j.1365-201x.1998.00356.x }}</ref>