John from the burg
Contributor
Nothing wrong with hyper ventilation as long as you don't exceed safe limits.
Maybe if your going for a record w redundant professional supervision but spearfishing is dynamic and cant be perfectly planned like a record dive.
Every single major freedive training organization discourages hyper ventilation, its not just about how much air you can pack in your lungs, co2 and o2 and lactic acid all have effects on your brain and muscles. In my spearing circles no one packs or hyper vents, thats amateur stuff used as a replacement for actual training.