system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What happens in the body when people faint because they see blood?
gpt
Sorry if this explanation isn't enough, when you see blood you become nervous,  so your body tries to calm you down, but is an overshot and  it reduces the blood pressure too much, that mean your brain doesn't receive enough oxygen to function properly and it power down aka faint.