THE SCIENCE OF SWEAT

We all do it, but many regard "sweating" as too personal to discuss. Regardless of its suitability as a topic for polite conversation, sweating is serious stuff, as a look at the anti-perspirant selection in any drug store or grocery store will confirm. At Gillette, we too take the subject seriously -- so seriously that we've raised it to the level of science.

Here's what we have learned:

Why Do We Perspire?
Perspiring is a normal, vital body function. It is essential in the regulation of body temperature, cooling the body as it evaporates and eliminating certain waste products as well.

Although perspiration doesn't have an odour on its own, odour becomes a factor when the sweat emitted by certain glands is broken down by bacteria on the skin -- a particular problem in the underarm area where bacteria thrive. As far back as the first century B.C., humans used aromatic oils to mask body odour. Today's technologically advanced deodorant and anti-perspirant products offer a variety of options for stopping underarm odour and/or wetness.

Glands At A Glance
Ever wonder how we sweat? It's an age-old question that has a three "gland" answer. Sweat secretions are produced by millions of sweat glands located all over the body and are stimulated by heat or emotional stress. The human skin contains three types of sweat glands: sebaceous, eccrine and apocrine. Each performs a unique function in human chemistry.

Sebaceous Glands: Moisturizing Skin
The sebaceous glands -- or "oil glands" -- are located primarily on the scalp, face, chest and back, numbering approximately 3,000 in each square inch of skin. Sebaceous glands produce sebum, a natural skin oil which is a complex mixture of fats and waxes. These glands are present at birth, but begin to secrete sebum actively following the onset of puberty.

Located at the side of hair follicles, these glands secrete sebum through a small duct inside the hair shaft. The sebum locks in the skin's natural moisture and prevents it from drying out.

Eccrine Glands: Body Temperature
The average human has between two and three million eccrine glands all over the body, but concentrated in the palms, soles and underarms. Exercise, hot weather, fever and emotional stress stimulate eccrine sweating. The colourless and mainly odourless sweat produced by eccrine glands is mostly water, but also contains inorganic chlorides and low levels of fatty acids. Eccrine sweat aids in regulating body cooling and in the removal of some waste products.

Apocrine Glands: The Odour Factor
Apocrine glands are located primarily in the underarm and genital regions. There are approximately 2,000 apocrine glands in the average human body. Like sebaceous glands, apocrine glands secrete their contents to the skin surface through hair follicles.

Apocrine glands secrete a milky sweat that is rich in organic materials. This secretion, when broken down by bacteria on the surface of the skin, is the chief cause of body odour. This sweat is produced in response primarily to hormonal stimulation and secondarily to emotional stimuli such as fear and pain. Apocrine glands are present from birth, but do not mature and secrete until the onset of puberty. Therefore, body odour is not usually a problem for children, and is rarely a problem for the elderly as the secretions of apocrine glands are reduced with age.

Did You Know?

	Animal Attraction In other mammals, it is believed that apocrine glands produce body odours [Pheromones] that serve as a lure to attract mates.
	Body Heat Rising Heat is the primary cause of perspiration, with emotional an environmental factors also playing a role. Generally, 200 milligrams an hour of perspiration are secreted through the underarm at room temperature (without the use of an antiperspirant). During strenuous exercise, these levels of perspiration can rise to 700 mg/hour.
	Keeping Your Cool Perspiration acts as nature's own "air conditioner." When body temperature rises, the blood vessels dilate and bring blood to the skin's surface. At the same time glands release their sweat to the surface of the skin where it evaporates and therefore cools the blood. This cooled-down blood then circulates throughout the body and reduces the overall body temperature.
	Extreme Sweating Excessive sweating is called hyperhidrosis. Individuals who suffer from hyperhidrosis often have sweat literally pouring off of them. In most cases, the cause of the condition is unknown, but it is treatable through a variety of medical techniques.