system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: how do we store stress in our bodies?

Is this just a throw away phrase or do we actually store mental/emotional stress in our physical bodies? If so, how?
gpt
Stress doesn't literally get "stored", but it *is* true that frequent stress is bad for you.

When you're in a stressful situation, your brain secretes chemicals called "adrenaline" and "cortisol" into your blood.  These chemicals signal your various body parts (including the brain again) that you're in a situation where short-term survival needs to be prioritized over long-term health.

This basically increases your susceptibility to all kinds of illnesses.  Physical resources that would have gone to your immune system instead get diverted to your muscles.  Mental resources that would have gone to helping you adapt better to your environment instead get diverted to being on the lookout for immediate threats.  Etc.