system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is that split second stomach dropping feeling when we get frightened?

Edit: The specific feeling is like that fight or flight response. Not like the horror movie feeling jump scare, but like if someone pulls a gun on you type feeling. Does anybody else have 2 different feelings/reactions when scared?
gpt
That's likely a Sympathetic Nervous System response from a surge in adrenaline. It reduces blood flow to your non vital organs like skin/GI which is what makes you pale/clammy and causes the funny feeling in your gut.