system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How can a psychological factor like stress cause so many physical problems like heart diseases, high blood pressure, stomach pain and so on?

Generally curious..
gpt
None of these responses seem at the ELI5 level. Let me try:

"Stress" is your brain thinking there is a threat and telling your body "do what you have to so you can get through *right now* and we'll sort it out later." So your body floods itself with chemicals that it thinks will help you overcome whatever threat the world has thrown at you - this is when people talk about "super human strength" for example.

The goal of this is to fight off a bear or out run another predator. These chemicals that get dumped into our body are highly toxic to us in the long run, but what does that matter if you die to this threat *right now*? 

The issue for public health is that your brain is setup for living in the wild and doesn't know that an unexpected meeting with your boss is not a threat to your life. So now we have a situation where we are constantly dumping toxic chemicals into our bodies for prolonged periods which causes all the problems you mentioned.