[HangnJudge]

I used to do the same thing when I was young and ignorant.
I was amazed, though, at how long I could hold my breath.

I used to practice breathholding after hyperventilation

Records:
swam 3 lengths of swimming pool underwater
Held breath once for 4'45”

I don't recommend it to others, but
it did, powerfully, teach self control

What it does is strip the CO2 from the blood stream
Most breathing efforts are driven by
raising CO2, not lowering O2

Drastically dropping CO2 levels can cause
the breathing reflexes to simply "forget" to breath

[NonValueAdded]

Just out of curiosity, isn’t that a recipe for SIDS?