system
Given the following post, respond as if you're commenting on Reddit:
human
Eli5 Why does saliva taste like blood when you exhaust yourself?

Why does your saliva start to taste like blood if you ride your bike up a hill or run fast for a while?

Edit: Thanks for the Awards and the nice Comments.
Also blew up bigger than I thought!
gpt
When you complete a quick, strenuous exercise, some excess hemoglobin is released from your blood cells into the lungs, which is then moved to your mouth during an exhale. Since hemoglobin is also made up of iron, that is what your receptors detect- hence the blood taste.