[timewizard]

Ah the wisdom has changed. This was more often taught when I was younger, which yes, was quite a while ago. The warnings given then were don't go for depth with this method, exhale occasionally while underwater, and manage your breath again immediately on the surface.

[OxO4]

Freedivers are also taught not to exhale underwater, because it wastes oxygen and lowers your CO2 level, making it harder to know when you actually have to come back up. Your body can't sense the level of oxygen it has, so freedivers rely on CO2 levels as a proxy, so messing with it is dangerous.

[nikitoci]

And you also becoming much less buoyant and will not surface without actively swimming or pulling the line.

[FrojoS]

Interesting. Got a good source? I should definitely look into this again.

[jboggan]

https://www.divessi.com/en/get-certified/freediving https://www.padi.com/education/freediving https://www.freedivinginstructors.com/ https://www.aidainternational.org/Education/AIDAFreedivingCo...

I've only taken the SSI training but I guarantee none of the different freediving organizations will recommend the type of breathing you are discussing, and in fact a large part of the intro course hammers home that you don't breathe that way.

[literalAardvark]

Any freediving course. You have to breathe normally for an extended time, then dive, then take an extended break, hyperventilation just makes it easier for you to get yourself killed.

[timewizard]

The people around the pool and lake where I grew up? From what I'm reading while searching it seems that "hyperventilate" is probably a bad term for the type of breathing I was shown. We wouldn't do it until we felt a conscious change like dizziness but more like 4 to 8 good deep full and fast breaths before holding, enough to notice, but not so much that it presented the dangers I'm now reading about.

[Azrael3000]

That is still considered hyperventilation as a freediver, even though you might not feel any symptoms. The suggestions you gave in your previous post are dangerous and should not be done. Please take a proper course to learn about free diving physiology and safety. Otherwise this sport can get dangerous very quickly.