Sweat vi­tal to body health

Di­a­betes can al­ter body odour

The Star Early Edition - - HEALTH - JI­NAN HARB

SWEAT smells bad, stains clothes and em­bar­rasses us in pub­lic. But it’s vi­tal to health, keep­ing our bod­ies cool dur­ing ex­er­cise, on a sunny day or when we eat cer­tain foods such as chilli.

We also pro­duce sweat when we feel under pres­sure, as part of our stress re­sponse.

Here, the ex­perts re­veal the lat­est un­der­stand­ing about sweat’s role in health and how to keep it under con­trol.


We have nearly four mil­lion sweat glands in our skin which pro­duce up to 25ml of sweat an hour to reg­u­late our body tem­per­a­ture, this can rise to two to four litres an hour dur­ing ex­er­cise, says Ge­orge Havenith, a pro­fes­sor of en­vi­ron­men­tal phys­i­ol­ogy and er­gonomics at Lough­bor­ough Univer­sity.

Al­most two mil­lion peo­ple in the UK suf­fer from ex­ces­sive sweat­ing or hy­per­hidro­sis. They can’t func­tion nor­mally: they have to change their shirt every hour or can’t shake hands with peo­ple, says Dr An­ton Alexan­droff, a con­sul­tant der­ma­tol­o­gist at the Univer­sity Hos­pi­tals of Le­ices­ter NHS Trust.

We’re los­ing mois­ture through our skin all the time, but don’t no­tice be­cause the air makes most of the liq­uid evap­o­rate quickly, says Havenith.

“Peo­ple who say they don’t sweat are wrong,” he adds. If we didn’t sweat, we would col­lapse and die half-an-hour into a run as our body tem­per­a­ture would rise too much.

The dif­fer­ence in sweat lev­els lies in how sweat is dis­trib­uted be­tween glands: some peo­ple feel it ex­ten­sively as it all comes out of one area, for ex­am­ple the fore­head.

“In peo­ple who say they don’t sweat, the per­spi­ra­tion is just more evenly dis­trib­uted across glands, so doesn’t build up a layer of liq­uid that they no­tice,” he ex­plains.

We pro­duce two types of sweat: the watery sweat that cools us down, and an oily liq­uid that may be linked to sex­ual at­trac­tion.

Cool­ing sweat is pro­duced by the ec­crine glands, found just under the skin all over the body. When our body heats up, the hy­po­thal­a­mus, the tem­per­a­ture cen­tre of the brain, in­structs these glands to pro­duce sweat: this evap­o­rates on the skin, tak­ing heat from our bod­ies.

“We pro­duce seven times more watery sweat than the oily kind be­cause of its role in pro­tect­ing us from over­heat­ing,” says Dr Jus­tine Hex­tall, a con­sul­tant der­ma­tol­o­gist at West­ern Sus­sex Hos­pi­tals.

This sweat is pro­duced by fil­ter­ing fluid in the ec­crine glands. Salts are ex­tracted back into the blood if they are needed and the re­main­ing salty liq­uid passes out as a fluid onto the skin, ex­plains



The sec­ond type of sweat is pro­duced by the apoc­rine glands in the armpits, gen­i­tals and nip­ples. They pro­duce an oily liq­uid full of fat, and pro­tein an­i­mal stud­ies sug­gest this sweat con­trib­utes to sex­ual at­trac­tion.

Though it’s odour­less when re­leased, once this sweat is on the skin, it re­acts with bac­te­ria such as Sta­phy­lo­coc­cus ho­mi­nis, pro­duc­ing mal­odor­ous by-prod­ucts.

A hairy armpit has a big sur­face for de­bris and bac­te­ria to ad­here to so tends to be more smelly, says Havenith.

“Peo­ple from east Asia typ­i­cally don’t have body odour be­cause they have a gene that means they don’t pro­duce cer­tain pro­teins that would be con­verted by bac­te­ria into odours.

“This type of sweat can be trig­gered by hor­mones such as cor­ti­sol, and is re­leased at times of stress or ex­treme emo­tion. It’s part of our fight or flight re­sponse. A small amount of sweat on our hands and feet im­proves the fric­tion in our skin and helps us grip,” says Havenith.

Teenagers’ sweat tends to smell be­cause their fluc­tu­at­ing sex hor­mones stim­u­late the apoc­rine glands to re­lease oily sweat, says Hex­tall. “Be­cause of the habits teens tend to have such as not wash­ing odour-caus­ing bac­te­ria builds up.”


Some sweat glands are more ac­tive than oth­ers. One the­ory is that heat ex­po­sure be­fore the age of four de­ter­mines how well your glands cool you down, says Havenith.

That’s why peo­ple who grow up in the trop­ics sweat more than those who hol­i­day there, be­cause more glands are ac­tive and these ac­ti­vated glands are also more ef­fi­cient at cool­ing the body down, pro­duc­ing more sweat.

Hav­ing a tat­too might also make you sweat less, as the ink­ing dam­ages sweat glands, ac­cord­ing to a study pub­lished ear­lier this year in the jour­nal Medicine and Science in Sports and Ex­er­cise.


In gen­eral, over­weight peo­ple sweat more, says Alexan­droff. They have to ex­ert more en­ergy when ex­er­cis­ing to move their weight and they have a big­ger sur­face area to cool down.

The more fat a per­son has, the harder it is to cool down and the more sweat they need to pro­duce, says Hex­tall.

Fit peo­ple also sweat a lot dur­ing ex­er­cise be­cause their bod­ies have adapted to be more sen­si­tive to tem­per­a­ture change and are more ef­fi­cient at sweat­ing to keep the body cool, says Havenith.


If you shower daily you’ll re­move bad bac­te­ria so you shouldn’t smell, says Alexan­droff. An­other trick is to use an­tiper­spi­rant be­fore bed. Women who do this have been shown to sweat less than those who use the prod­ucts first thing in the morn­ing.

An­tiper­spi­rants gen­er­ally con­tain alu­minium chlo­ride. Alu­minium par­ti­cles are taken up by cells in the sweat glands, caus­ing them to swell and close up so they no longer re­lease sweat. It is thought that by ap­ply­ing it at night, the an­tiper­spi­rant has time to set in the pores dur­ing sleep.

Dry your armpits and ap­ply an­tiper­spi­rant at night, says Hex­tall. What’s left on the skin will ir­ri­tate some peo­ple so in the morn­ing, have a shower.


Some peo­ple sweat more when eat­ing foods such as peanut but­ter. This is thought to be a mild al­ler­gic re­ac­tion. “The body may per­ceive cer­tain trig­gers as harm­ful and flush them out through sweat,” says Havenith.

Hot cof­fee or tea can also make you sweat as it stim­u­lates tem­per­a­ture sen­sors in the body, which set off your body’s cool­ing mech­a­nism. And caf­feine can stim­u­late the ner­vous sys­tem to ac­ti­vate sweat glands.


What you eat can af­fect sweat odour. Gar­lic or as­para­gus can give off a pun­gent odour be­cause chem­i­cals in these foods are not bro­ken down and are re­leased in breath and sweat, says Alexan­droff.

A high-pro­tein diet can also lead to mal­odor­ous sweat, par­tic­u­larly if you’re ex­er­cis­ing, adds Hex­tall.

If you don’t have enough carbs, your body will start to break down pro­tein as fuel, which re­leases am­mo­nia in sweat, lead­ing to an am­mo­nia-like smell.

This scent could also in­di­cate that the liver or kid­neys aren’t work­ing prop­erly.


For some, the is­sue is not down to ex­cess sweat but the wrong type of bac­te­ria on their skin caus­ing ex­cess odour.

Ear­lier this year, re­searchers at the Univer­sity of Cal­i­for­nia sug­gested a treat­ment for this: a bac­te­rial trans­plant.

Sci­en­tists stud­ied iden­ti­cal twins, one with body odour, the other with­out. They took a swab of bac­te­ria from the fresh-smelling twin and smeared it into the armpit of the smelly one.

The odour dis­ap­peared, even a year later. The the­ory is that the new bac­te­ria out­num­bered the bad, elim­i­nat­ing the odour.

“It is like a pro­bi­otic that im­proves odour,” says Alexan­droff.

Di­a­betes and other meta­bolic con­di­tions can al­ter body odour. This is be­cause they lead to a build-up of tox­ins in the blood which are trans­mit­ted to the sweat, which can then be de­tected as acidic or rot­ten ap­ple scents, ex­plains Havenith.

Pa­tients may also have nerve dam­age as a re­sult of un­con­trolled blood sugar lev­els, says Dr Hex­tall. – Daily Mail

‘Dry your armpits and ap­ply an­tiper­spi­rant at night’


TEM­PER­A­TURE: An­tiper­spi­rants are most ef­fec­tive when ap­plied be­fore sleep at night.

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