Sweating Under Stress

woman stressed at workRemember those times that you really wanted to stay cool, calm and collected—and next thing you knew, big dark rings of sweat formed under your armpits and your palms felt all clammy?

As you may know, stress—as well as heat and physical activity—can trigger the sweat glands. But, did you know that sweat from stress may cause an odor even worse than if you'd worked out at the gym or sat in the sun on a hot summer day? That's because stress produces a different type of sweat than the other two major causes of sweat. 

Causes and Types of Sweat

Sweat from environmental heat or physical activity is produced by your eccrine sweat glands, while sweat caused by stress comes primarily from your apocrine glands.

You have 2 to 4 million sweat glands, most of which are eccrine glands. These glands cover most of your body but are concentrated on your palms, the soles of your feet, your forehead and cheeks, and, of course, your armpits. When your body temperature rises—from heat or movement—your autonomic nervous system signals the eccrine glands to secrete sweat. This sweat is made up mainly of water, with small amounts of proteins, lipids, salt and other substances. The perspiration on your skin cools your body as it evaporates. It also helps hydrate your skin and balance your body fluids and electrolytes.

Apocrine glands are found in areas where you have lots of hair follicles, such as your armpits and genital region. These glands are larger and secrete a thicker sweat that contains more lipids and proteins. When you're stressed, the glands force the sweat to the skin's surface. Scientists believe that this fattier sweat produces more nutrients for bacteria to feast on, and, thus, more body odor.

Several recent studies found that participants could identify from the odor whether or not sweat samples were produced by someone experiencing emotional stress.