Skincare Treated

How Do The Sweat Glands Work?

Sweating or perspiring is one of those involuntary functions of the body that are beyond our control. But to understand why we sweat and what happens when the process spins out of control, let’s take a look at the sweat glands.

The sweat glands are coiled tubes embedded in the lower layer of the skin called the dermis. The average human being has about 3 to 4 million sweat glands all over the body, except on the lips, nipples and the genitals.

What Triggers The Glands?

The sweat glands respond to various stimuli. Temperature, more specifically a rise in temperature, is the primary stimulus.

When the temperature rises, the sweat glands produce sweat which rises to the skin’s surface, from where it evaporates and cools the skin. This is called thermoregulation or the body’s ability to regulate temperature.

Strong emotions like fear and anxiety also trigger the action of the sweat glands, which are activated by the sympathetic nervous system. This is that part of the nervous system that controls the automatic or involuntary functions of our body.

The human body has two types of sweat glands – eccrine and apocrine sweat glands. They differ in the kind of sweat they produce, the age at which they are first activated and the location on the body.

Types of Glands

Eccrine sweat glands produce a watery substance comprising mainly salts like sodium, chloride, potassium, urea, bicarbonate and calciums as well as amino acids. It is colorless and largely odorless.

The apocrine glands, on the other hand, produce sweat that also contains proteins, fatty acids and ammonia. This is a thicker, white, milky substance that tends to stain the clothes.

While the eccrine sweat glands are located all over the body with a concentration on the palms and soles of the feet, the apocrine glands are located mainly under the armpits and in the anal-genital area.

The reason apocrine sweat has a foul odor is that is due to bacterial decomposition.

Eccrine Versus Apocrine

Another difference between the two types of sweat glands is that eccrine glands are activated at birth while apocrine glands are activated at puberty.

Oddly enough, the apocrine sweat glands seem to be an evolutionary held-over as they seem to serve no function in human beings. In mammals, they produce pheromones that are essential to mating and territorial behavior.

Sweat Production

So just how do sweat glands produce sweat? The eccrine sweat glands first need to be stimulated either by a trigger such as a sudden rise in temperature or a bout of exercise or a powerful emotion.

Once triggered, the glands draw on water stored in the spaces between the cells in the glands. This water is drawn into the glands from the blood in the surrounding capillaries in the dermis.

The gland then secretes high concentrations of sodium and chloride and a low concentration of potassium.  The sweat is then pushed upwards towards the pore, from where it is released onto the epidermis.

Sweat is produced by the apocrine sweat glands also contains proteins and fatty acids.

What gives sweat its typical odor? Sweat itself is odorless. It is the sweat from the apocrine sweat glands that has a distinct smell. This happens when the bacteria on the skin’s surface metabolize the proteins and fatty acids.