Eli5 Why do they say take 3 or 4 deep breaths before a deep dive?

Question

Eli5 Why do they say take 3 or 4 deep breaths before a deep dive?

In: Biology

Answer 1

From what I think I know, lack of oxygen isn’t what makes you want to breathe when underwater, It’s the buildup of carbon dioxide. By taking a few deep breaths, you get as much carbon dioxide out as possible, to extend the buildup time when underwater