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

It’s a combination of purging CO2 from your lungs and oxygenating your blood. As a teen I used to hyperventilate at the poolside until dizzy and then bash out underwater lengths. Notably increases the duration you can stay under, I was never able to cover 50m without this