We've all been there. You're in an office waiting room and nervously awaiting a job interview or doctor appointment, and then it hits. You feel that first flush of warmth, and then the dam bursts. All of a sudden, you start sweating--from the palms, underarms, forehead, and places you didn't know could even produce sweat. It happens to all of us, but why? What is it about anxiety that turns us into clammy, dripping messes?
Well, there's actually a scientific explanation, believe it or not--two explanations, in fact. First, we need to examine how anxiety works. Essentially, anxiety acts on the autonomic nervous system, which is responsible for regulating all those body functions that happen automatically and unconsciously, such as respiration and heart rates, digestion, blinking--and yes, sweating.
When anxiety strikes, it kicks the autonomic nervous system into overdrive and activates the so-called fight or flight response. If the brain thinks there's a threat, it tells the body to get ready to defend itself or run away.
Whichever path you choose, the result is ultimately the same. Blood is automatically diverted from less important areas and functions like the stomach and genitals, since you probably won't be too concerned with eating or having sex when you're in a do-or-die situation. Part of this process includes shedding excess water through the pores in your skin rather than through the kidneys.
This process isn't foolproof, of course; there's a reason why it's not uncommon to wet yourself in a moment of extreme fear. So you can look at it that way: increased sweating, as embarrassing as it may be, still beats the alternative.
The other primary reason we sweat is to cool off. When our body temperature rises, we naturally begin to sweat to bring the temperature back down. That's also why we usually sweat buckets when a fever breaks; once the body's back in fighting form, it starts bringing the temperature down by cooling the surface of the skin with sweat.
Unfortunately, anxiety and the entire fight or flight response also raise our internal temperature. Cue the sweating, whether mild or intense, to try to turn down the heat before our internal organs get cooked.
But why the underarms? To put it simply, we have sweat glands pretty much everywhere, but they're highly concentrated in our palms, feet, groin, face, and (you guessed it) the underarms. Although we often sweat more in one area than others, most of us will sweat from the underarms at least some of the time. Add anxiety and stress to that, and you've got the perfect recipe for armpit stew (with our apologies for that terrible mental image).
There's even worse news, too. Anxiety sweat is different from the sweat you produce during exercise or while out on a hot day. Basically, there are two types of sweat glands: eccrine and apocrine. Eccrine sweat glands are found all over the body, and the sweat they produce is mostly just water. The apocrine glands, meanwhile, are found in places like the armpits and groin, and they produce sweat made up of lipids and proteins. The bacteria living on your body love this type of sweat, and it's when they break it down for food that you start to get that tell-tale funky odor. And where do you usually sweat when anxiety rears its head? That's right: exactly the same places where these bacteria are waiting for their next meal. Hence, anxiety sweat tends to smell worse than the sweat you experience just as a result of hot weather.