Sweating is necessary. Sweating through the skin is the physiological response to an increase in body temperature during physical exercise or because of excessive heat. Sweat evaporation cooling the body is the mechanism by which temperature is regulated. If this mechanism fails even death may result. But some people sweat excessively and, for them, hyperhidrosis is a very annoying problem.
The skin has three types of sweat glands. The most numerous are the eccrine glands, responsible for thermoregulation by sweating. They are distributed over all the skin, but are particularly to be found in palms, soles, armpits and the face; the apocrine glands, primarily located in the armpits, nipples and perineal area, are responsible for body odour. Humans have between two and four million eccrine sweat glands distributed all over the body surface and averaging about 600 per square centimetre. A person can sweat several litres per hour and up to ten litres in a day. Read more
Our genes determine what our skin secretes in sweat and, consequently, how we smell. No two body odours are alike as we all have our own unique “cocktail” of bacteria that break down sweat to release volatile substances. But there are people who do not smell ... and they even use deodorant.
Our body odour develops when skin bacteria degrade certain substances produced by the sweat glands: steroid hormones, fatty acids and sulphur compounds. Our genetic characteristics determine the amount and proportion of each such substance secreted and, consequently, differences in how we smell. However, in a recent UK study of 6 500 women it was found that 2% had virtually no smell because of their particular version of the ABCC11 gene. However, over 75% of these women used underarm deodorant – out of habit. Identifying this genetic trait could lead to odourless people both saving money and reducing their exposure to chemicals. Such studies also open the way for the future application of genetics to the field of personal hygiene.
Alum crystal, used by ancient civilizations, has come back into fashion with the rise of natural cosmetics. It has many properties, including as a body deodorant. How does it benefit the skin? Is the aluminium it contains hazardous?
Alum crystal is a naturally occurring sweet-tasting mineral that looks like translucent glass. It is usually composed of an aluminium sulfate and a sulfate from another metal. The most commercially exploited alum is the hydrated form of potassium aluminium sulfate (potassium alum), which comes from a volcanic igneous rock called aluminiferous trachyte; it can also be manufactured industrially, however. Read more
Human skin has a unique healing mechanism shared with no other mammal. Recent research suggests that our sweat glands contain a reservoir of stem cells that are recruited to repair damaged skin.
Each square inch of our skin has, on average, 600 sweat glands, triple the number of hair follicles. On a normal day we segregate a litre of liquid through these orifices, but up to ten litres a day in extreme circumstances. A study by the University of Michigan (USA) has shown that humans have a unique healing mechanism – lacking in the skin of other mammals – that is based on stem cells stored in the sweat glands. The enormous regenerative potential of such stem cells could help develop new wound therapies. Researchers hope, for instance, to improve treatments for ulcers in diabetic patients and bed sores in hospitalized patients, as the corresponding healthcare costs are substantial. The research could, in fact, open up new avenues for skin care in general.