Take chewing gum for example.
When agitated people chewed gum, they felt less anxious, more alert and had less cortisol (the stress hormone) in their saliva.
By chewing gum, are you increasing blood flow to your head? Is that extra blood flow helping with alertness and also distracting you from the stressful factors around you?
Maybe by chewing gum you’re tricking your lizard brain (the oldest and simplest part of your brain) into feeling that if you’re chewing, everything must be okay so there’s no need for anxiety and the stressful cascade of things that entails.
But what about this. Most gum is sweet tasting. We’re hardwired to seek out sweet foods. So maybe chewing something sweet is soothing because of the taste.
Chewing gum could also be considered form of fidgeting. You’re just using your mouth for chewing instead of wringing your hands when you’re nervous.
Some people like feeling busy. If you’re busy chewing maybe you feel like you’re somehow being busy and by feeling busy your attention is diverted.
Maybe what happens you chew come is some combination of these possibilities. It’s hard to know sometimes exactly what’s happening.