system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 Why do we subconsciously hold so much tension in our bodies?

I constantly find myself clenching my jaw even if I just unclenched it. I’ve done some yoga where we focus on each part of the body and let go of all the tension little by little. So why are we holding all his tension? It causes headaches and I’m sure other pain. It doesn’t make any sense.
gpt
Stress activates our fight or flight response, which causes our muscles to tense because tense muscles react more quickly, which means we can get away from any possible danger quicker. This was an evolutionary trait that allowed us to escape the dangers of the natural world better. In today's world, stress is less caused by things like an approaching predator and more caused by things like our jobs. Even though we don't need to jump out of the way of things, every day stress still makes our bodies tense because that's what they were trained to do over centuries of evolution.