The oldest know medical document, the Ayurveda, appeared in Sanskrit in 568 BC and considered sweating so important to health that it prescribed the sweat bath and thirteen other methods of inducing sweat. Throughout history physicians have extolled the medicinal value of the sweat bath in its various forms such as the Finnish sauna, Russian banai, Islamic hammam, or the American Indian sweatlodge. Today, enthusiasts claim that beyond being relaxing the sauna gives relief from the common cold, arthritis, headaches, hangovers and "just about anything that ails you." Even if these claims are somewhat exaggerated, medical evidence shows that bathing in temperatures of 9O degrees C (192 degrees F) has a profoundly beneficial effect on a healthy body.

Sweating

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

[*The physiological effects of different sweat baths are not the same, due to variations in heat and humidity. For example, the body sweats more profusely in the hotter (80-100 degree C) and drier (15-25%) atmosphere of the Turkish bath, where moisture on your body is often merely condensation. 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 aprocine 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. Like the baseball batter who wets his hands for a better grip, it is believed 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.

Skin

Heating and Cooling the Inner Body