Sweat!

I was prompted to Google after reading another thread an came across this interesting article. I have also heard that when it comes to "choosing" a mate we select partners who have "opposite" immune systems (this can be detected through smelling them) so that when we breed we have children with a broader, stronger immune system. I've also heard that women on the contraceptive pill select partners with the same immune scent as themselves therefore limiting the immunity capabilities in their children. there is a theory that there are more hereditary diseases these days because women are on the pill when they choose a mate with the same weaknesses as themselves. Interesting. (Fortunately I wasn't on the pill when i chose DH!)

From TimesOnline

Smell differs almost as much from person to person as fingerprints do. Whereas a magnifying glass and the latest high-tech kit are needed to recognise a fingerprint, everyone is subconsciously taking note as they appraise other people?s smell. This requires nothing other than an olfactory system that, when healthy, is so acute that the brain can assess the smell without the person even being aware of the odour.

Everyone has a unique smell known as an odortype ? hence we can recognise others by their smell. This may either attract, repel or leave one unmoved. Professor Tim Jacob, of Cardiff University, has researched into smell and its effect on sexual and personal attraction. One theory that he supports is that someone?s smell varies according to their immunotype. People are likely to be attracted most strongly by those with a histocompatibility complex ? ie, a different immune type ? different from their own. Being attracted by someone with a different, but compatible, immune system is one way in which, should bonding lead to mating, any resulting offspring could be better equipped to deal with, for example, a flu pandemic.

Our body odour is dependant on the constituents of the sweat produced by the apocrine (sweat) glands. These are modified around the nipple, groin, genitalia and under the arm so that their secretions are likely to be especially pungent. To a lesser extent, the sweat glands on the cheeks, eyelids, ears, temple and scalp produce similar secretions. This is one reason why people may nuzzle up to those areas although they wouldn?t immediately seem to be erotic.

The sweat contains steroid compounds, especially the 16-androstenes ? these are particularly profuse in the sweat produced by the groin and armpits. Once bacteria have acted on the sweat they break it down and that gives it its individual smell.

The more androstene that a person?s sweat contains, the greater the potential for him or her to be strong smelling. It has been found that two of the 16-androstene compounds are important in this respect. If there is a predominance of androstenol, the sweat from the armpits and kindred areas tends to smell markedly musky; if there is a predominance of androstenone, the sweat develops an obvious smell of urine. There is another compound that sometimes gives rise to the slightly acrid sweaty armpit smell that can be differentiated from either the musky or uriniferous smelling sweat of the skin of the erogenous areas.

It seems from the reader?s letter that he is sweating excessively only because he?s taking heavy exercise. Sweating is not only inevitable but a useful heat-losing device. As long as he exercises at this rate he?ll continue to sweat. Equally inevitably there will always be innocuous bacteria on his skin that will be able to break down sweat so that the potentially smelly steroid-like compounds within it will release their distinctive smells. I suspect that his sweat contains an excess of androstenone, hence the smell of urine.

The skin of the wrist often sweats profusely ? giving rise possibly to the habit of kissing a woman?s hand ? and may, like that of the eyelids or cheeks, possibly produce sweat rich in 16-androstenes.

The uriniferous smell of androstenone will be picked up by leather. This will also harbour bacteria capable of breaking down the sweat. I?d suggest a metal watchstrap, cleaned with a disinfectant swipe. It is a myth that excessive smell is the result of lack of hygiene. Some people may have a strong smell despite regular washing. These 16-androstene-rich people, I fear, just have to wash more often to lessen the impact.

Our reader asks if smell could be related to any particular disease. It is true that some diseases that produce a particular smell. The smell of diabetic patients is an obvious one; if their condition is poorly controlled and blood sugar levels are high, they smell of acetone. Doctors are well attuned to the smell of cirrhosis and other causes of liver failure. Experts can smell lung cancer on the breath of their patients and doctors in my youth claimed to be able to differentiate between the smell of diphtheria and that of scarlet fever. Trained dogs are adept at sniffing out cancers of the bladder. It is claimed that the sweat of people with some psychotic diseases is identifiable.