GeniesLoki

might be using a different discomfort threshold, I mean like when it stops feeling effortless

yes, yes

Hmm, yeah, though you don't achieve long breath holds with effort. It's more like relaxing into it. You can't "do" breath holding, you really do have to stop doing the thing that prevents you from holding your breath.

Forcing yourself to hold your breath for longer is the sign that you're about to fail. The actual process is more like "Hmm I notice that I want to breathe. Do I actually need to breathe or am I OK? I'm OK I think, so I'll just relax and enjoy myself. I can always breathe later."

I should probably try this framing the next time I do breath hold exercises.

The key part is basically to relax. If you tense up then your body starts going "I'm using muscles so I need oxygen now!!!" and it's all over.

Yeah I always have problems relaxing into a hold near the end. I typically get about 60s if I don't hyperventilate as a warmup (like with Wim Hof). Although there's this interesting phenomena I noticed if I do relax past the I really need to breathe, I clock another 30secs easy

Try three candle breaths instead of hyperventilating first. Deep breath in, rapid exhale out, repeat three times then on the fourth breath in hold.