Imagine you are at the dentist. You are sitting quietly in the waiting room with several other people around when he comes out of his room and calls your name. All you can think about is how nervous you are. Your heart pounds, you feel tense, there's that awful wetness in the palms of your hands, your face feels unbearably red and hot and you start feeling sick. Or how about that presentation at work that you have been worrying about for weeks? Even thinking about it is making you sweat! You may think that sweating is nature's little joke. Why do certain events make us so stressed out and sweaty?
Well, anxiety elicits a body response called fight or flight -- your body's way of preparing you for a potential threat. While seeing your dentist isn't really a threat, the lower, more primitive, part of your brain, which controls basic body functions, doesn't know that and acts like you are being threatened. Ultimately, the hypothalamus -- a part of the autonomic nervous system -- is responsible for your anxious sweating. When faced with a stressful situation, it tells your adrenal gland to release dozens of hormones, including adrenaline. Adrenaline is responsible for causing you to sweat.
Some of us sweat mostly from our apocrine glands when we're anxious (such as those in the armpits), while others sweat more from the eccrine glands (found on the rest of the body). Eccrine sweat is bad enough because it can mean loads of awful sweat! But in addition to potential pit stains, apocrine sweat can make you smell bad because it's full of fatty acids. This makes it prime fuel for bacteria that live on the skin, which create that bad body odor. Anxious sweating can be a vicious cycle—worrying about whether others can see your sweat or smell body odor makes you feel even more anxious, which in turn, is causing you more sweat. Oh, no! Everyone is looking at me now, sweating as I am, walking into his room!
But why is any of this good for us?
When the fight or flight response is activated, your heart begins to beat faster and stronger, resulting in increased blood pressure. This gets more blood into your muscles up ready for fight (fight) or making sure you run faster (flight). Blood flow is diverted away from your fingers and toes, which can result in paleness and tingling sensations, ensuring that if you were to be injured by some hoard of rampaging zombies, you are less likely to bleed to death (maybe this is why you never see anyone using deodorant in action films?). You also experience rapid breathing, which works to get more oxygen to your vital organs (e.g. lungs) and thus makes you able to run faster—although, this type of breathing can also lead to dizziness, if you don't actually run anywhere. Your pupils also widen so that you can more easily see your escape route. You also begin to sweat, which in addition to keeping you from overheating, will make you slippery and harder to catch. Also, if you were to grab a branch of tree or something to fight your enemy away, your palms would be less likely to be injured. And, just in case you were thinking of having a snack before starting to run, your whole digestive system will shut down, from the saliva glands (resulting in dry mouth) to the stomach (producing nausea or constipation). Your body needs to be as light as possible to be able to run fast (causing you to actually be physically sick). So, next time you reach for the can of deodorant, ask yourself one thing, do I really want to stop myself sweating?