Fun fact - Sweat

Sweating is as essential to our health as eating and breathing. It accomplishes three important things: get rid of wastes in the body, regulates the critical temperature of the body at 37 degrees C (98.6 degrees F), and helps keep the skin clean and pliant.

Many people, in this sedentary age, simply don't sweat enough, making sweat bathing particularly desirable. Antiperspirants, artificial environments, smog, synthetic clothing, and a physically idle lifestyle all conspire to clog skin pores and inhibit the healthy flow of sweat.

[The length of time spent in the sauna differs from time spent in other types of sweat baths. In this section, results peculiar to the sauna are noted.]

When you lounge in a sweat bath, heat sensitive nerve endings produce acetylcholine, a chemical which alerts the 2.3 million sweat glands embedded in the skin. But not all of them respond. The apocrine sweat glands, located in the pubic and arm pit areas, are activated only by emotional stimuli. They carry a faint scent whose purpose is believed to arouse the sex drive.

Nevertheless, the eccrine sweat glands, by far the most abundant, respond to heat. During a 15-minute sauna, about one liter of sweat is excreted, depending upon the individual. (Normal daily rate ranges from .5 to 1.5 liters.) Eccrine sweat is clear and odorless; any odor is only created by the presence of bacteria. One of its chief functions is to cool the body by evaporation, although there are also eccrine glands on the palms of your hands and soles of your feet which react to emotional stimuli. It is believed that these sweat glands were intended to provide us with a good grip on clubs, rocks or vines when our survival often depended upon them. Sweat glands on the feet provided greater traction when it came time to run.

Another kind of sweat, called insensible perspiration, originates inside and works its way through blood and other cells to the surface of the skin. Even without a sweat bath, approximately a liter of insensible perspiration evaporates each day.

A modified type of sweat gland is the milk-producing mammary gland. Some mothers in Finland believe the sauna encourages the breast's ability to produce milk, although this hasn't been established scientifically.

Sweat also has the function of being a judicious garbage collector. During a 15-minute sauna, sweating can perform the heavy metal excretion that would take the kidneys 24 working hours. 99% of what sweat brings to the surface of the skin is water, but the remaining one percent is mostly undesirable wastes. Excessive salt carried by sweat is generally believed to be beneficial for cases of mild hypertension. Some mental hospitals use saunas in their rehabilitation programs to pacify patients.

A metabolic by-product, urea, if not disposed of regularly, can cause headaches, nausea and, in extreme cases, vomiting, coma and even death. Sweating is such an effective de-toxifier that some physicians recommend home saunas to supplement kidney machines. Sweat also draws out lactic acid which causes stiff muscles and contributes to general fatigue. Sweat flushes out toxic metals such as copper, lead, zinc and mercury which the body absorbs in polluted environments.