What is sweat?
Sweating or perspiration is the loss of body water through the sweat glands in the skin.
Sweat gland
People sweat to keep their body temperature. Sweat glands occur throughout the skin, but in the hands, feet and armpits most sweat glands are present. Sweat consists mainly of water and salt, but it also contains ortho-cresol and cresol, which have an antiseptic effect. A man produces per day between 100 and 8000 ml of sweat, depending on conditions such as weather and physical exertion. We can distinguish two types of sweat glands:
Exocrine
Exocrine sweat glands occur over the entire body and play an important role in the thermoregulation of the body temperature. When the body is likely to be overheated by example, exercise, or fever may by producing sweat the wetted surface of the skin allowing the body cools easier.
Apocrine
Apocrine sweat glands spread the familiar odors. They are not located all over the body, but in some regions of the skin. These are the armpits, the skin around the anus and around the nipples. In childhood, these apocrine sweat glands have not developed that begins at puberty under the influence of sex hormones. Until the moment when this oily sweat from the glands on the surface of the skin comes, it is odorless. To the skin surface, however, the sweat is converted by bacteria into substances having the characteristic odor of sweat. Apocrine sweat is produced in small quantities by the day and is hardly affected by exercise or emotion. However, the sweating may evoke emotions. Usually, these emotions are not very positive, although the sweating in certain situations can induce or enhance sexual feelings.
Disorders sweating
- Hyperhidrosis: too much sweating. Can be localized (armpits, palms) or generalized.
- Anhidrosis: can not sweating. May occur in certain congenital syndromes (forms of ectodermal dysplasia) or nerve damage.
- Bromhidrose: unpleasant smelling perspiration can be the result of bacterial colonization on the skin or (rare) metabolic diseases. Someone can only fear that his sweat stinks.
- Chroomhidrose: colored sweat.
- In cystic fibrosis, the salt can not be properly removed from the sweat.
- Dyshidrotic eczema is eczema with blisters on palms and soles. Often there is hyperhidrosis. However, the exact relationship between sweat and eczema is not clear.
- Miliaria is a skin with blisters caused by blocked sweat glands.
Transpiration in sociology and history
Although sweating is a natural reaction of the body, sweating is not appreciated in everyday life. One uses therefore sprays that prevent perspiration. Casanova wore pads in the armpits of his clothing. In ancient times one is ashamed perspiration because that would indicate a lack of self-control. Xenophon says that the Persian youth not perspiring wanted to be seen, these humors were in constant physical exertion, heavy labor and a modest life (so they thought), after all, have evaporated or dried. From this reasoning, the phrase "the lazy sweat" approach.
The expression "blood sweat" seems to stem from the New Testament. It is written that Jesus Gethséhamé on the eve of his death: "And being in an agony he prayed more earnestly: and his sweat was like drops of blood falling down to the earth.". Although not in the Bible that Jesus really sweated blood phenomenon is sometimes associated with hematidrosis. This disorder is a spontaneous reaction to stress very rare, there are six known scientifically substantiated cases.
Animals
Some animals, like dogs, have hardly sweat glands. They can in warm weather only other ways to lose their excess body heat, for example by saliva to evaporate their tongues by panting.