system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: By what mechanism does the body force you to take another breath after you've held it for a long time?
gpt
O2 levels in the blood fall. CO2 levels rise. Acidity of blood rises. Hypothalamus in the brain can detect this change, notifying the brain the O2 levels are getting dangerously low. Instincts kick in, and forces the diaphragm to take in another breath.

Correct me If im wrong please (I might be)