Well, for me it's that sometimes I start heavily stuttering right before I will breath again. Basically stuttering at the word before I will breath which then goes like this. I am running out of breath -> nervous -> stutter more-> nearly passing out and feeling my chest crumbling into itself -> really loud inhale My chest hurts a bit for a while after it. It doesn't happen that often but when it does I feel like I will pass out, even my vision starts to get blurry.