Talk:Perspiration

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Discussion of the active nature of the perspiratory process would be useful. For example, various proteins must be involved in passing water from the inside of the cellular membranes in sweat glands to the outside, possibly with concomittant processes for minimising salt excretion as discussed below. Such processes must use energy.

At a macro level, for example, exactly how much metabolic energy is required to excrete 1L of sweat at normal body temperature in humans?

In this section:

Sweat contains mainly water. It also contains minerals, as well as lactate and urea. Mineral composition will vary with the individual, the acclimatisation to heat, exercise and sweating, the particular 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[7]. 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 - 0.8 mg/l), iron (1 mg/l), chromium (0.1 mg/l), nickel (0.05 mg/l), lead (0.05 mg/l).[8][9] Probably many other less abundant trace minerals will leave the body through sweating with correspondingly lower concentrations. In humans sweat is hypoosmotic relative to plasma.[10]

People DO NOT sweat sodium or potassium, (pure metal ions) they sweat sodium chloride, potassium chloride, along with sulphates (I am led to believe) etc.

This misinformation makes it hard to get an accurate picture of the (mean) composition of the mineral content of sweat.

It needs to be revised as it could be construed as "sodium" meaning sodium chloride or phosphate ect., at 0.9g L OR sodium as a part of the sodium chloride molecule, in which only HALF of the sodium in the sweat is sodium, as the other half is the chlorine atom. —Preceding unsigned comment added by 210.1.214.106 (talk) 01:48, 10 November 2009 (UTC)

It is not misinformation... It is meaningless to speak of "sodium chloride" or "potassium sulphate" when they are in a mixed solution such as sweat. If you evaporate the water you will have a mixture of sodium chloride, sodium sulphate, potassium chloride and potassium sulphate, even if you originally added only two of those substances. There is no way to determine what the dry ingredients were before they went into solution, only that they contained sodium, potassium, chloride and sulphate. In effect, "sodium chloride" only exists as a solid; it is how sodium and chloride ions arrange themselves in the absence of water. Secondly, "sodium" means "sodium". Sodium at 0.9g/L can be made using 2.3g/L sodium chloride, or 3.1g/L sodium sulphate. It is not that half of the sodium in sweat is sodium; you are thinking that sometimes "sodium" could mean "sodium chloride" or salt. It doesn't; whenever you see "sodium" it means just that... sodium. When you see that something contains 100 mg of sodium, it could mean that it has 230 mg sodium chloride, or 310 mg sodium sulphate, or a mixture of many different sodium compounds. (124.168.202.62 (talk) 12:08, 30 January 2012 (UTC))

The solute mg/liter in the main article should include both the anion and the cation. Since sulfate and other ions are at trace concentrations in sweat, considering sweat to be water and sodium chloride is a suitable approximation.

Correction to the previous Talk entry. 254 mg of sodium chloride contains 100 mg of sodium. The previous entry says 230 mg, which is incorrect.

The relative atomic mass of sodium (Na) is approximately 22.98976928 (Isotopes of sodium). The relative atomic mass of chlorine (Cl) in natural isotopic proportions is approximately 35.453 (Isotopes of chlorine). Because sodium chloride (NaCl) has one atom of each element, the mass of one mole of sodium chloride is the sum of the two atomic masses. The ratio of the mass of sodium chloride to the mass of sodium is (m(Na)+m(Cl))/m(Na) is approximately 2.5421. This means that the mass of sodium chloride corresponding to 100 mg of sodium is 254 mg, not 230 (the binding energy is less than 1% of the mass). Drbits (talk) 00:02, 22 August 2016 (UTC)

Sweat and attraction

Do we have any information about the potentially attractive nature of sweat - is sweat used to attract mates (talking from a more historical perspective here)? Tompagenet 10:43, 23 Aug 2003 (UTC)

Pheromones are present in sweat. --Dante Alighieri 10:45, 23 Aug 2003 (UTC)

Salty!

OK, I don't know if anybody else was puzzling over this, but I was wondering why sweat is salty -- you need those salts, and companies like Gatorade do good business selling you a way to put salts back in when you exercise. Why don't you sweat plain water?

I found an answer here, from Dr. Stephen Cheung (it's the second interview; direct link to MP3).

If you can't listen to the sound file (it's not very long), the short version is:

• your sweat glands get the fluid, indirectly, from the plasma in your bloodstream
• the fluids in your body are naturally salty
• as you may have suspected, there's no advantage to sweat being salty, so...
• your sweat glands also act as a filter to try to keep the salt in your body; that is, sweat is *less* salty than what's in your body... Did you know that dried sweat can be mistaken for dried chicken urine? If not thats because only scientists know that, but now so do you.

Neat.

Disclaimer: I'm not a doctor, and everything I know about this, I know from that link.

Untrue. I tasted some normal saline a few days ago. Much less salty than the sweat of my brow. Sweat is salty so it evaporates quicker and cools the skin more rapidly. JFW | T@lk 10:03, 15 Apr 2005 (UTC)

According to the saline page, saline has the same osmolality as blood. Plasma (which Dr. Cheung says eventually becomes sweat -- you're not sweating red blood cells) makes up only half of your blood, and it's the half with the salt, so it should be about twice as salty as saline. I don't think the fact that saline tastes less salty than sweat negates anything I said (or heard).

Also, IIRC, you've got it backwards: salt water evaporates more slowly, not more quickly, than fresh water. (A web search seems to confirm this -- here, here, or here.)

I gladly admit that it's possible Cheung's explanation isn't correct, but it sounds reasonable to me, and I'm not yet convinced that it's untrue.

Good sources; normally, the internet is lousy as a physiology source.

It could actually be that the whole purpose of sweat saltiness is to delay evaporation, i.e. to prolong its effectivity to stave off heat. You could be correct that sweat is less salty than blood: sweating gives a reference of 35-65 mmol/L sodium, which is much less than the serum sodium content of 135-145 mmol/L (which, incidentally, is serum so with the blood cells removed).

Furthermore, to sweat water without electrolytes would damage the body's internal milieu: hypernatremia (high sodium load) would be so severe the kidneys would lose their concentrating ability, leading to paradoxical excessive fluid loss through the renal tract in addition to the cutaneous losses. JFW | T@lk 09:41, 17 Apr 2005 (UTC)

Evolution has a habit of finding clever ways of adapting processes to a different task. So, perhaps the salt assists the skin's immune response, controls bacterial growth, conditions our 'fur', or does some other function unrelated to heat loss? Perhaps the question is related to why tears are salty? StuFifeScotland 13:53, 27 October 2006 (UTC)

Sweating is also the practice of employing women and children in low-wage professions that require long hours of tedious efforts without relief. May 3rd, 2005 23:54 Z

The body moves water mainly by pumping salts, water follows the salt because of osmotic pressure. Sweat at the base of the sweat gland has the same amount of salt as blood, but as the sweat moves up the sweat gland tube some of these salts are reabsorbed. At higher sweat rates a lowere percentage of salts are reabsorbed.

It also should be noted, that whereas the original sweat has not got that large concentration of salts, but as it continuously evaporates, the salt concentration may rise many-fold. So finally the sweat gets more salty than the body interior. (83.208.147.243 (talk) 15:05, 4 September 2011 (UTC))

normal sweat response

When exercising it is normal to start sweating at the forhead then down the rest of the body. Is it normal to sweat more a few minutes after one has completed exercising than one did while working out?

toxins

"...for example, in a sauna, helps the body to remove more toxins, is without scientific support. [3] " the source cited relies entirely on the opinion of one expert, Dr. Dee Anna Glaser, who also happens to be a founder of a group that treats people for excessive sweating. Her whole business depends on people thinking that sweat is dirty, embarrassing and that it produces zero positive effect. So yeah, she is going to say that sweat doesn't remove any toxins. — Preceding unsigned comment added by 99.240.218.173 (talk) 21:51, 5 September 2011 (UTC)

there are a lot of claims all around that sweating carries toxins from the body. most commonly, from the armpit, groin, behind the knees and ears. i can't find any information on this. what do you guys know? Dreamer.redeemer 08:58, 21 January 2006 (UTC)

i've found no information whatsoever on this. perhaps they were misinformed and thought sebum was a toxin. i think it's safe to say there are no toxins in sweat anywhere on the body. Dreamer.redeemer 04:26, 31 January 2006 (UTC)

Sweating is a good thing apprectiate it for what it is.

It's spin from sauna freaks. JFW | T@lk 22:21, 31 January 2006 (UTC)

Am I misinformed when I think lead is a toxin? Fugyoo (talk) 12:18, 7 July 2011 (UTC)

Contradiction in the articles on Urea and Sweating

I hope this is the right place to post this. This is my first comment.

The article on Sweating states that "Sweating (also called perspiration or sometimes transpiration) is the production and evaporation of a watery fluid, consisting mainly of sodium chloride (commonly known as salt) and urea in solution, that is secreted by the sweat glands in the skin of mammals."

The article on Urea states: "Many researchers used to believe that a small amount of urea was excreted (along with sodium chloride and water) in human sweat. However that was proved wrong when Dr. M. Falk determined at RC Institute that only sodium chloride and water are excreted from sweat.”

I don't know for sure which is correct but sweat either contains urea or it does not. Whoever wrote the paragraph at the article on Urea seems certain that sweat does not contain urea while the article on Sweating states that it does.

I have left this same comment at both articles on Urea and Sweating.

What is it used for in non-human animals?

Do any non-human mammals use sweating for temperature regulation? What it the purpose of sweating in the other mammals? Won't the fur get all wet? AxelBoldt 20:09, 4 March 2007 (UTC)

Slightly answering your Q: Dogs sweat out of their tongues, hence no wet fur.

WRITE SOMETHING ABOUT hematidrosa (sweating with blood, rare phenomenon) !!! —Preceding unsigned comment added by 195.225.92.155 (talk • contribs) 21:45, 7 June 2007

Cleverly Disguised Vandalism?

The sentence "Normally if you carry excess body weight, you tend to sweat quite excessively around the armpit area.", seems like a fancy way of saying, "Fat people have very sweaty armpits." I suspect that this may be vandalism, worded in such a way as to try and avoid detection. If it's not, the article should cite a source.Apofisu (talk) 19:40, 8 January 2008 (UTC)

Why the pronunciation?

Why is it pronounced like "swet" but spelled like "sweet"? I'm really curious and would like an answer. Please. <3

The vowel combination ea has several different pronunciation patterns in English: Compare bread, beard, mead, heart, heard-- 71.236.26.74 (talk) 19:50, 24 July 2009 (UTC)

Urea Content of Sweat

On 20:05, 3 July 2008, user 84.70.217.236 added the line "This substance contains urine". I've changed this to indicate that sweat contains a small amount of urea, as per the Wiki article and talk page for urea, where the question of sweat's urea content seems to already have been resolved. Note: I'm no expert. Dblanchar (talk) 14:05, 5 July 2008 (UTC)

Picture

Seriously, is this the best picture we can get to illustrate "sweat"? I mean, seriously. I'm sure there are MANY better ways to illustrate the concept. This seems like an appeal to a juvenile sense of comedy..."ooh, lookit--fer 'sweat' they got a pic of a sweaty fat guy!!! Now let's go write 'POOP' and 'U R TEH GHEY' on the Main Page!"GJC 21:26, 24 April 2009 (UTC)

Can someone more skilled than I crop the sweaty guy picture? The picture seems staged as a vanity shot (couple-y portrait for no good reason). —Preceding unsigned comment added by 98.248.53.86 (talk) 17:04, 23 January 2011 (UTC)

Propose locking the Perspiration page

There is an excessive amount of vandalism on this topic. Suggest that it be locked. Some people, like myself, want to LEARN about scientific and medical topics, and don't appreciate other people's childishness.

Volume

Could s.o. find a reference for volume of sweat e.g. during activity, rest etc. Maybe from an old antiperspirant research page? Just to provide some idea for comparison. THKS 71.236.26.74 (talk) 19:53, 24 July 2009 (UTC)

Treatment for Excessive Perspiration caused by Medication

I am on a high doseage of Methadone, 95ml and have been for about 3 years and although my intention is to decrease it slowly I am unable to at the present moment and probably for a fair while. One of the reasons for this is that I suffer from clinical depression and coming of while I am suffering a bad time is not recommended due to possible relapse to my previous use of Heroin.

I have been stable on this amount as I said for about 3 years and for the most part it suits me to use it. However as I am on such a high doseage I suffer terribly from excessive perspiration, I find that if I take even the shortest walk and I get warm, my clothing gets soaked and my face and hair gets very wet. This is a fact that is contributing amongst other things to my depression as I find this extremely embarrassing and I do not like to go out as I feel that people are constantly staring at me and commenting.

Is there anything that you can suggest that may help this. I am not expecting miracles, but something that may help a small amount even so I can try and start up a social life again which is another reason for my depression.

I shower regularly and I don't find that I smell, but its just the actually perspiration that is a problem and I am prepared to try anything that may help.

Another thing is that I am on HRT - 2mg Zumenon - and that this does not help, however the persperation is not like a hot flush as it doesnt happen at any other occasions other than when I am exerting myself. I am slightly overweight, but not really that fat that it would cause this.

(RMLAIoM (talk) 13:44, 19 August 2009 (UTC))

Hope you can suggest something that may help me get some sort of life back!!! Oh strangely enough despite the fact I am in Menopause I do not suffer from night sweats!!!!

I am on a high dose of methadone to and i suffer with the same problem i cant walk anywhere with out being soaked with sweat and then my face get red and sweaty to. it is really embarrassing for me and people look and talk or ask me are u okay do u need something And all i want to say to them is yes i do i need to stop sweating. please if u have any information about what to do to stop sweating so much write back.i asked the pharmacy they said bowtox i dont have time to do that nore the money..thank u

                             Rosella goodeye  —Preceding unsigned comment added by 24.67.34.75 (talk) 21:16, 12 February 2010 (UTC) 

eh?

maybe i'm wrong, but aren't purity and solute-ness mutually exclusive?

Quote: "Sweat is not pure water; it always contains a small amount (0.2–1%) of solute. When a person moves from a cold climate to a hot climate, adaptive changes occur in their sweating mechanisms."

Surely something is either pure, or a solution, ie; "In chemistry, a solution is a homogeneous mixture composed of two or more substances".

So either something is mixed, or its pure. Or am i missing something here?IAmTheCoinMan (talk) 03:53, 21 November 2009 (UTC)

Perspiration in spinal cord injured people

Hi, I think it might be interesting to point out that people with spinal cord injuries (like me) lack of perspiration and that makes us impossible to control our body temperature. If we are exposed to intense heating such as direct sun exposure for a certain ammount of time, our inner body temperature rises. I got no place to quote it from, but perhaps you might wanna research on this. --190.246.146.156 (talk) 18:45, 8 August 2010 (UTC)

Ketones in Sweat

I find it unusual that there is no mention of ketones being secreted in sweat, despite the recent study that found that people with high levels of ketones in their sweat are less likely to get bitten by mosquitoes.

<a href="http://www.thefreelibrary.com/People+with+fruity+smelling+sweat+get+bitten+less+by+mosquitoes-a0207336375">People with fruity smelling sweat get bitten less by mosquitoes.</a>

Reiterate

The paragraph "A study has discovered that men, on average, start perspiring much more quickly than women, then twice as much when they are in the middle of exercising at the same relative intensity.[7] When men and women exercise at the same absolute intensity there are no differences in sweating responses." comes off as contradictory at first glance, would someone care to restate this with more clarity? —Preceding unsigned comment added by 99.241.156.201 (talk) 00:29, 15 February 2011 (UTC)

Lymphatic system

There is mentioned here in discussion, that "your sweat glands get the fluid, indirectly, from the plasma in your bloodstream". This is not exactly correct. The sweat liquid (saying "water" is insufficient) also (or primarily?) gets from the Lymphatic system, where it drains impurities and Inflamation residues. It also contains trace amounts from the food: It has been shown, that vitamine B prevents ticks from attacking people, since they feel it from the sweat (which also holds for beer drinking). The sweat of carnivorous people also smells differently, and the sweat of ill people also may smell much worse than that of normal people.

So the scientist, mentioned earlier on this discussion page, saying that "Dr. M. Falk determined at RC Institute that only sodium chloride and water are excreted from sweat" - probably on some people that may be right, but absolutelly not for all people in all circumstances! (It rather seems, that he neglected all other content being below his poor detection limits?)

So the sweating may be of no good use for absolutelly healthy and pure people, but it may speed up lymphatic system removal of illness residues, which is why people sweat more when they are ill, which is why the body temperature rises during illness... This is also the healthy effect of sauna - draining more the lymphatic system. This is also, why it is said "one needs to sweat the illness out" (a rough translation from my native language) - which is exactly what happens - the immune system destroys bacteria in tissues and lymphatic system drains the residues mainly (although not only) through sweating... (83.208.147.243 (talk) 15:05, 4 September 2011 (UTC))

Urea makes sweat yellow fallacy

I deleted the part of the photo description stating that sweat stains are "yellow from urea", yet it still remains on the jpg's own page. It is a common fallacy that urea is responsible for the yellow colour of sweat stains and urine. Urea is a colourless substance and it's good solubility in water would make urea stains easy to remove. — Preceding unsigned comment added by 202.236.145.97 (talk) 10:21, 28 February 2013 (UTC)

Thanks for doing that. Since the photo is in the "Composition" section, there's an implication that something in sweat causes the yellow stain. However, the best sources I've found agree that oxidised sebum is the source of the yellow colouration. Sebum is excreted through sebaceous glands, not sweat glands. But if this is the cause, one still needs to know if and how the process of sweating embeds sebum in clothing. Sebum is mostly oil and sweat is mostly water, so they don't mix but they might emulsify under certain conditions. If they do emulsify, what are the conditions? Since a "sweat stain" may actually be a sebum stain, I'm removing this photo from the section for now. —Ringbang (talk) 18:49, 16 March 2016 (UTC)

@Ringbang: As the photo taker, I think I should offer this explanation (after the same thing was pointed out to me about urea when I added the image to that article): It's my shirt and my sweat and the stains are very much real. However ... I was diagnosed with hyperbilirubinemia a while back, which in my case (ahem) seems to produce no symptoms save for the slightly yellowish sclera when viewed from the side (and maybe that my teeth never quite seem totally white, and having to let any one taking my blood, particularly for donation purposes, know in advance as otherwise the high bilirubin levels result in it getting thrown out for donation as it would otherwise be a possible sign of hepatitis). Would that be a more likely cause of the yellow stain? Based on the article, which says that bilirubin is the real reason for the color of urine, I wonder if that might have something to do with it, because it looks identical to a urine stain.

Also, I have another picture, not yet uploaded, showing the white residue at the front of sweat stains on a dark shirt I wore on a hot summer day. Is that powdery stuff urea left from evaporation?

All the same, we probably could have just amended the cutline to say that this is an example of a sweat stain experienced by some people. I will certainly amend the description at Commons as a result of this discussion. Daniel Case (talk) 04:56, 31 March 2016 (UTC)

Image

Sweating after exercise.

The facial sweat of a boy

I reworded the unencyclopedic tone of the caption, but I question how much this image is really contributing to the topic. I understand that people would want at least one such image for the infobox, but 2 are unnecessary. Consider removing one. Lesion (talk) 19:28, 20 August 2013 (UTC)

I think the latter image, of the boy is incorrect and should therefor not be used. Based on the picture this seems just te be water dripping down from wet hair (from bathing or swimming). 9 year olds don't sweat that much. Mvg, Basvb (talk) 21:24, 27 October 2013 (UTC)

Agreed. I have removed the infobox image. Arbitrarily0 ^(talk) 17:40, 30 December 2013 (UTC)

The remaining picture is also incorrect. The man is "sweating" profusely from his shoulders and back but not at all from his armpits. Not likely. Sweating looks more like this. Yappy2bhere (talk) 21:24, 3 July 2015 (UTC)

 Fixed I replaced the photo. Ringbang (talk) 16:09, 16 March 2016 (UTC)

Does perspiration on the skin cool

Maybe a little more on how sweat works & doesn't work? Does perspiration on the skin in and of itself contribute to cooling of the body much like water dumped on the body? This seems totally logical. But apparently this is not the case. Perhaps someone can explain the science of this a little bit better. According to a coworker, wiping the sweat off rather than leaving it the body cools the body quicker. I came to this page in hopes of finding biological information on this matter. Perhaps someone could adjust the article accordingly? 174.103.231.69 (talk) 01:58, 2 December 2013 (UTC)

Concentration of trace metals

The concentrations of trace metals seem too high. Perhaps the author wrote millicgrams (mg) instead of micrograms (μg)? — Preceding unsigned comment added by 179.159.188.37 (talk) 16:36, 23 October 2015 (UTC)

Information about cold sweat

Information about cold sweat can be given as it is different from that of exercise induced sweat. Thank you. -- Abhijeet Safai (talk) 06:21, 2 May 2017 (UTC)

Eccrine glands and apocrine glands

This article says that two types of sweat glands are found in the human body - eccrine glands and apocrine glands. It says that eccrine glands are found all over the human body, but it does not clarify how apocrine glands differ from eccrine glands. Vorbee (talk) 17:10, 15 July 2018 (UTC)

Unit conversion in Lead

The lead says: "2–4 liters per hour or 10–14 liters per day (10–15 g/min·m2)" . How does a flow rate get converted into a rate involving mass in the second range? And if the conversion IS ok, shouldn't it also be applied to the first one, too? JezGrove (talk) 22:55, 27 July 2020 (UTC)

Infobox changes

In addition to 'Body odor', Symptoms should include 'Droplets of salty water on skin'.

'Drinking water' does not prevent perspiration. Madhatter10-6 (talk) 19:04, 14 August 2021 (UTC)

This article should be about sweating. Not treating it as a disease/disorder.

This article is written like an article about a disease or disorder. Sweating is a normal and necessary bodily function. Granted, there are cases of excessive sweating, possibly due to a disease/disorder, but… 155.4.221.27 (talk) 21:41, 12 October 2022 (UTC)

West Side Arts Coalition

Which date's newsletter features "Fall for Art: A Fine Arts Exhibition"? Achmad Rachmani (talk) 22:27, 8 July 2023 (UTC)