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Why do we sweat after running? Also we sweat sometime after drinking lots of water. Why it is so? Can someone please enlighten me in this regard?

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up vote 8 down vote accepted

Exercise, such as running, increases muscle activity. This increases the energy demand of these tissues, which increases the rate of cellular respiration. Respiration releases heat as a by-product, therefore the body is hotter during and after exercise.

Sweating is a homoeostatic mechanism to keep core body temperature constant. It is a response to lower the body temperature. When the body becomes too hot, sweat is released onto the surface of the skin. The water from the sweat then takes some of the excess heat energy from the body and uses it to evaporate. Because water has a relatively large specific heat capacity a lot of heat can be carried away by this method.

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But I sweat even after I lots of drinking water.... what could be the reason here? – gpuguy Jul 9 '12 at 14:01
@gpuguy Do you mean you sweat after exercise even if you drink water? Or do you mean that at rest, in a cool room when one wouldn't usually sweat, you drink a lot of water and then begin to sweat? – Ben Jul 10 '12 at 17:28
i meant: "that at rest, in a cool room when one wouldn't usually sweat, you drink a lot of water and then begin to sweat?" (especially some time after having dinner/lunch) – gpuguy Jul 10 '12 at 17:37
  1. If the meal you eat is hot, you will get some heat and if your body will consider it as excessive heat, it will try to get rid of some by making you sweat.

  2. Drinking water and sweating after a meal may be coincidentally related and probably caused by hot meal rather than water. A side note: When you are dehydrated, you sweat less and when well hydrated you can sweat "normally," but drinking water by itself does not stimulate sweating.

  3. Some people with "reactive hypoglycemia" can sweat and get anxious after meals. In this case, after a meal, food passes through the stomach rapidly to the small intestine, where glucose from the food is quickly absorbed and raises blood glucose level considerably. This triggers excessive insulin release that allows quick uptake of glucose by the cells resulting in drop of blood glucose under the normal level (hypoglycemia). This triggers the release of adrenaline, which breaks down some glycogen from the liver to produce glucose. Adrenaline also triggers sweating.

  4. Certain underlying neurological conditions (not necessary diseases), such as increased tonus of the vagal nerve (that supplies the gut) can make you sweet more in certain circumstances.

  5. A meal can be a "stress" (psychological or physical) which can trigger the release of adrenaline, which makes you sweat (just like in anxiety from any cause).

Sources: Diaphoresis (excessive sweating) Reactive hypoglycemia Mayo Clinic

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protected by Chris Sep 9 '14 at 5:40

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