What i meant is i have severe pain and misery holding my breath for a long time and i can do so only for 1 minute or so even with hyperventilating. What I meant is that with a lot of apnea training , co2 tables etc. If i could get my breath hold to 4 minutes it might be easier to blackout for me underwater. I want to be able to tolerate co2 better . i can't stand it now so it's hard to even hold my breath for long. I haven't been able to blackout yet in air . i haven't even gone into the water yet. So i could blackout now? I guess i need to learn how to swim too though.
Note: i'm trying out several suicide methods. Trying to decide on one. I do have severe ADHD so that could be why i haven't decided yet.
I don't think you understood the point.
The pain you feel when holding your breath is the urge to breath that starts with diaphragm contractions and that move to glottis contractions later because co2 is building up and o2 is fading.
With c02 training you simply get used to suffer and tolerate high levels of co2 building up that trigger the need to breath to slowly push your performance.
The more you train the more you can fight and thus suffer.
I did never hyperventilate before a dive so I didn't cheated the baseline c02 levels, which in theory shorten the timing span between realising you need to breath and blackout, but I can say from my experience that the urge to breath underwater it's a complete nightmare.
In my opinion for your situation will be a terrible method.