The Y-Factor with Christian McLean

No Sweat

Everybody sweats. Most of us know the main reason (i.e. it is the body's attempt at cooling itself). While this is something we learned when we were young, I thought I'd go deeper into the world of sweat and explain a little extra.

You're probably wondering why I chose to write this article now, in the colder months instead of during the summer. Part of the reason is that in the winter months, while wearing several layers and walking swiftly to avoid prolonged exposure to the cold air, your body heats up rather rapidly and once you enter the heated indoors your body gets a sudden dose of even more heat. It begins to sweat in order to get the temperature back down to its average and you're left pealing off layers and layers in an attempt to quell it.

Behind every drop of sweat is an entire biological system. Below the surface in the layer of skin called the dermis there are over 2.6 million sweat glands. These glands are a series of cells, which form a hollow tube in the shape of a coil in the dermis as the reaches the outer part of the skin, the tube straightens out. There are actually two different types of sweat glands, the Eccrine and the Apocrine. The Eccrine are far more common and cover the entire body including the palms of the hands. The Apocrine glands are reserved to the armpits and groin. Besides location four characteristics set these two glands apart. The Apocrine glands are larger and end in hair follicles instead of pores. They become active at puberty but not before and the sweat they produce contain proteins and fatty acids. It is these proteins and fatty acids which have a milky yellowish color that cause the armpits of shirts to stain yellow (yup, that's why).

The obvious reason why we sweat is that it regulates the body's temperature. If the temperature rises our bodies produce more sweat. The sweat draws heat from the skin and as it evaporates it cools the body. But not all sweat evaporates. Much remains a liquid, hence it pouring down your face after an intense workout. On humid days even more remains a liquid because there is too much moisture already in the air.

Physical exercise and a rise in temperature are obvious reasons why we sweat. There is a direct correlation with these things and the rise in body temperature. But sweaty palms are another thing entirely. Sweating can reflect emotional states; fear, anxiety, nervousness. Emotions like these trigger a response by sending a message to your adrenal glands to increase epinephrine production. This in turn triggers the sweat glands.

There's a liquid coming out of your body all the time, don't you want to know what it is? Sweat is primarily water, but it also has high concentrations of chlorine and sodium along with a small amount of potassium. This fluid goes from the coil of tube in the dermis out through to the skin. Depending on the speed of sweating, the chemical consistency of sweat can change. At a low rate of production, most chlorine and sodium is reabsorbed through the cells compiling the tube, which connects the coil to the outer skin. Once heavy sweating kicks in, the body cannot reabsorb the chlorine and sodium as much so more leaves the body. It is the cells' inability to absorb the sodium and chlorine in sweat which gives sweat its salty taste. If you remember basic chemistry the scientific name for salt is sodium chloride.

At our maximum, we produce a liter of sweat an hour. Those acclimatized to tropical heat can actually produce two to three liters an hour. With all that sweat, no wonder people have body odor right? Wrong. Sweat has no smell. You could produce your limit of three liters and still not be rank. The odor comes from a combination of bacteria and sweat. Bacteria metabolized the fatty acids and proteins produced by sweat from Apocrine glands. It is this process that creates the odor. Antiperspirants work because they contain an aluminum-based compound which helps swell shut sweat ducts. The aluminum ions are drawn into the cells, water is pulled in with the aluminum ions. Enough water enters that the cells expand enough to squeeze closed the sweat ducts and the ducts can't release sweat. By the way, in 2004 the FDA approved Botox injections in the armpits, which temporarily paralyze nerves, that trigger sweat glands.

Anyway, that's the basics of sweating, why you have yellow stains on your armpits and what antiperspirant does. Hope it didn't gross you out too much. It's your body afterall.

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