View source for Perspiration

{{Redirect|Sweat}}
{{Infobox symptom
| Name           = {{PAGENAME}} 
| Background     = 
| Image          = Amanda Françozo At The Runner Sports Fragment.jpg
| Caption        = The facial sweat of a runner
| ICD10          = {{ICD10|R|61||r|50}} 
| ICD9           = {{ICD9|780.8}} 
| ICDO           = 
| OMIM           = 
| DiseasesDB     = 
| MedlinePlus    = 
| eMedicineSubj  = 
| eMedicineTopic = 
}}

'''Perspiration''' ('''sweating''', [[transpiration]], or [[diaphoresis]]) is the production of a fluid consisting primarily of [[water]] as well as various dissolved solids (chiefly chlorides), that is excreted by the [[sweat gland]]s in the [[skin]] of [[mammal]]s.<ref name="perspiration">{{cite journal |url=http://www.jbc.org/cgi/reprint/99/3/781.pdf |title=Simultaneous Study of Constituents of Urine and Perspiration |author=Mosher HH |journal=The Journal of Biological Chemistry |year=1933 |volume=99 |pages=781–790}}</ref> Sweat contains the chemicals or [[odorant]]s [[Cresol|2-methylphenol]] (''o''-cresol) and [[P-Cresol|4-methylphenol]] (''p''-cresol), as well as a small amount of [[urea]].

In [[human]]s, sweating is primarily a means of [[thermoregulation]], although it has been proposed that components of male sweat can act as [[pheromone|pheromonal]] cues.<ref name="sweat">{{cite journal |author=Wyart C, Webster WW, Chen JH, ''et al.'' |title=Smelling a single component of male sweat alters levels of cortisol in women |journal=The Journal of Neuroscience |volume=27 |issue=6 |pages=1261–5 |year=2007 |month=February |pmid=17287500 |doi=10.1523/JNEUROSCI.4430-06.2007 |laysummary=http://www.berkeley.edu/news/media/releases/2007/02/06_sweat.shtml |laysource=UC Berkeley News |laydate=6 February 2007}}</ref> There is widespread belief that sweating, for example, in a [[sauna]], helps the body to remove toxins, but the belief is without scientific support.<ref>http://articles.latimes.com/2008/jan/28/health/he-skeptic28 You sweat, but toxins likely stay </ref> [[Evaporation]] of sweat from the skin surface has a cooling effect due to the [[latent heat]] of evaporation of water. Hence, in [[Temperature|hot]] weather, or when the individual's muscles heat up due to exertion, more sweat is produced. Sweating is increased by nervousness and [[nausea]] and decreased by cold. Animals with few sweat glands, such as [[dog]]s, accomplish similar temperature regulation results by panting, which evaporates water from the moist lining of the oral cavity and [[pharynx]]. Primates and horses have armpits that sweat like those of humans. Although sweating is found in a wide variety of mammals,<ref>{{cite journal |author=Goglia G |title=[Further research on the branched sweat glands in some mammals (Cavia cobaya, Sus scrofa, Equus caballus).] |language=Undetermined |journal=Bollettino Della Società Italiana Di Biologia Sperimentale |volume=29 |issue=1 |pages=58–60 |year=1953 |month=January |pmid=13066656}}</ref><ref>{{cite journal |author=Robertshaw D, Taylor CR |title=Sweat gland function of the donkey (Equus asinus) |journal=The Journal of Physiology |volume=205 |issue=1 |pages=79–89 |year=1969 |month=November |pmid=5347721 |pmc=1348626 |url=http://www.jphysiol.org/cgi/pmidlookup?view=long&pmid=5347721}}</ref> relatively few, such as humans and horses, produce large amounts of sweat in order to cool down.<ref>{{cite journal |author=McDonald RE, Fleming RI, Beeley JG, ''et al.'' |title=Latherin: a surfactant protein of horse sweat and saliva |journal=PLoS ONE |volume=4 |issue=5 |pages=e5726 |year=2009 |pmid=19478940 |pmc=2684629 |doi=10.1371/journal.pone.0005726}}</ref>

==Definition==
*Hypohydrosis is decreased sweating from whatever cause<ref>[http://www.allaboutsweat.com]</ref>
*Hyperhidrosis is increased sweating from whatever cause<ref>[http://www.allaboutsweat.com]</ref>
*Hidromeiosis is a reduction in sweating that is due to blockages of sweat glands in humid conditions.<ref>{{cite journal |author=Parsons K |title=Maintaining health, comfort and productivity in heat waves |journal=Glob Health Action |volume=2 |issue= |pages= |year=2009 |pmid=20052377 |pmc=2799322 |doi=10.3402/gha.v2i0.2057 |url=}}</ref>

==Mechanism==
[[Image:Man_Sweating_MIN.jpg|thumb|right|A man sweats after exercising.]]
Sweating allows the body to regulate its temperature. Sweating is controlled from a center in the preoptic and anterior regions of the brain's [[hypothalamus]], where thermosensitive neurons are located. The heat-regulatory function of the hypothalamus is also affected by inputs from temperature receptors in the [[skin]]. High skin temperature reduces the hypothalamic set point for sweating and increases the [[gain]] of the hypothalamic [[feedback]] system in response to variations in core [[temperature]]. Overall, however, the sweating response to a rise in hypothalamic ('core') temperature is much larger than the response to the same increase in average skin temperature. The process of sweating decreases core temperature, whereas the process of evaporation decreases surface temperature.

There are two situations in which our nerves will stimulate sweat glands, making us sweat: during physical heat and emotional stress. In general, emotionally induced sweating is restricted to palms, soles, armpits, and sometimes the forehead, while physical heat-induced sweating occurs throughout the body.<ref>{{cite journal |doi=10.1016/S0003-2670(97)00642-9 |first1=Tomoya |last1=Kameia |first2=Takao |last2=Tsudab |first3=Shinya |last3=Kitagawab |first4=Ken |last4=Naitoha |first5=Koji |last5=Nakashimaa |first6=Toshio |last6=Ohhashi |month=June |year=1998 |title=Physical stimuli and emotional stress-induced sweat secretions in the human palm and forehead |journal=Analytica Chimica Acta |volume=365 |issue=1-3 |pages=319–326}}</ref>

Sweat is not pure [[water]]; it always contains a small amount (0.2–1%) of [[Solution|solute]]. When a person moves from a [[cold]] [[climate]] to a [[hot]] climate, adaptive changes occur in the sweating mechanisms of the person. This process is referred to as [[acclimatisation]]: the maximum rate of sweating increases and its solute composition decreases. The volume of water lost in sweat daily is highly variable, ranging from 100 to 8,000 mL/day. The solute loss can be as much as 350 mmol/day (or 90 mmol/day acclimatised) of [[sodium]] under the most extreme conditions. In a [[cool]] climate and in the absence of [[exercise]], sodium loss can be very low (less than 5 mmols/day). Sodium concentration in sweat is 30-65 mmol/l, depending on the degree of acclimatisation.

==Composition==
Sweat contains mainly [[water]]. It also contains minerals, [[lactate]], and [[urea]]. Mineral composition varies with the individual, their [[acclimatisation]] to [[heat]], [[exercise]] and [[sweating]], the particular [[stress (biological)|stress]] source (exercise, [[sauna]], etc.), the duration of sweating, and the composition of minerals in the [[body]]. An indication of the minerals content is [[sodium]] 0.9 gram/liter, [[potassium]] 0.2 gram/liter, [[calcium]] 0.015 gram/liter, [[magnesium]] 0.0013 gram/liter.<ref>[http://www.ncbi.nlm.nih.gov/pubmed/18156662 "Sweat mineral-element responses during 7 h of exercise-heat stress," ''Int J Sport Nutr Exerc Metab'' 2007 Dec;17(6):574-82.</ref> Also many other [[trace elements]] are excreted in sweat, again an indication of their concentration is (although measurements can vary fifteenfold) [[zinc]] (0.4 mg/l), [[copper]] (0.3&ndash;0.8 mg/l), [[iron]] (1 mg/l), [[chromium]] (0.1 mg/l), [[nickel]] (0.05 mg/l), [[lead]] (0.05 mg/l).<ref>{{cite journal |author=Cohn JR, Emmett EA |title=The excretion of trace metals in human sweat |journal=Annals of Clinical and Laboratory Science |volume=8 |issue=4 |pages=270–5 |year=1978 |pmid=686643}}</ref><ref>{{cite journal |first1=Recep |last1=Saraymen |first2=Eser |last2=Kılıç |first3=Süleyman |last3=Yazar |year=2004 |title=Sweat Copper, Zinc, Iron, Magnesium and Chromium Levels in National Wrestler |url=http://mail.inonu.edu.tr/~tipdergi/include/getdoc.php?id=79&article=35&mode=pdf |journal=İnönü Üniversitesi Tıp Fakültesi Dergisi |volume=11 |issue=1 |pages=7–10}}</ref> Probably many other less-abundant trace minerals leave the body through sweating with correspondingly lower concentrations. In humans sweat is [[tonicity#Hypotonicity|hypoosmotic]] relative to [[Blood plasma|plasma]].<ref>{{cite book |title=BRS Physiology |edition=4th |first1=Linda S. |last1=Constanzo |page=155}}</ref>

==See also==
* [[Diaphoresis]]
* [[Hyperhidrosis]]
* [[Anhidrosis]]
* [[Hyponatremia]]
* [[Hyperthermia]]
* [[Body odor]]
* [[Hidradenitis suppurativa]]
* [[Pheromone]]s
* [[Sweat gland]]
* [[Sweat therapy]]
* [[Eccrine gland]]
* [[Apocrine gland]]

== References==
{{Reflist}}



== Further reading ==
*[http://www.allaboutsweat.com Encyclopedia of Sweat]
*{{cite journal |author=Sato K, Kang WH, Saga K, Sato KT |title=Biology of sweat glands and their disorders. I. Normal sweat gland function |journal=Journal of the American Academy of Dermatology |volume=20 |issue=4 |pages=537–63 |year=1989 |month=April |pmid=2654204 |doi=10.1016/S0190-9622(89)70063-3}}
*{{cite journal |author=Ferner S, Koszmagk R, Lehmann A, Heilmann W |title=[Reference values of Na(+) and Cl(-) concentrations in adult sweat] |language=German |journal=Zeitschrift Für Erkrankungen Der Atmungsorgane |volume=175 |issue=2 |pages=70–5 |year=1990 |pmid=2264363}}
*{{cite journal |author=Nadel ER, Bullard RW, Stolwijk JA |title=Importance of skin temperature in the regulation of sweating |journal=Journal of Applied Physiology |volume=31 |issue=1 |pages=80–7 |year=1971 |month=July |pmid=5556967 |url=http://jap.physiology.org/cgi/pmidlookup?view=long&pmid=5556967}}

{{commonscat|Perspiration}}

[[Category:Body fluids]]
[[Category:Exocrine system]]
[[Category:Animal physiology]]
[[Category:Reflexes]]
[[Category:Excretion]]
[[Category:Symptoms]]

[[ar:تعرق]]
[[ay:Jump'i]]
[[bh:पसीना]]
[[bs:Znojenje]]
[[br:C'hwez]]
[[ca:Suor]]
[[cs:Pot]]
[[cy:Chwys]]
[[da:Sved]]
[[de:Schwitzen]]
[[dv:ދާ]]
[[el:Ιδρώτας]]
[[es:Sudor]]
[[eo:Ŝvito]]
[[fa:عرق‌کردن]]
[[fr:Sueur]]
[[gan:汗]]
[[ko:땀]]
[[hi:पसीना]]
[[id:Keringat]]
[[is:Sviti]]
[[it:Sudorazione]]
[[he:זיעה]]
[[kn:ಬೆವರು]]
[[la:Sudor]]
[[lt:Prakaitavimas]]
[[mr:घाम]]
[[nl:Zweten]]
[[ne:पसीना]]
[[ja:汗]]
[[pl:Pot]]
[[pt:Suor]]
[[qu:Hump'i]]
[[ru:Пот]]
[[simple:Sweat]]
[[sk:Pot (tekutina)]]
[[sh:Znojenje]]
[[su:Késang]]
[[fi:Hiki]]
[[sv:Svettning]]
[[ta:வியர்வை]]
[[te:చెమట]]
[[th:เหงื่อ]]
[[tr:Ter]]
[[uk:Піт]]
[[ur:پسینہ]]
[[yi:שוויצן]]
[[zh-yue:汗]]
[[zh:汗液]]
[[Category:2Fix]]