system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why when we think about breathing we start breathing 'manually'?

And how do we forget about it suddenly 'automatic' breathing starts?

Thanks!.
gpt
Breathing is regulated by two different pathways, an automatic center that originates from your brainstem that controls your natural breathing when you are not actively thinking about breathing. There is also an area that comes from your cortex allows you to have active control of the muscles that are related to breathing (your diaphragm, your intercostals, your abs). When you actively try to take a deep breath/breath harder, you are overriding your autonomic breathing center, and actively using more of your secondary respiratory muscles.