Agonizing way to go. CO2 buildup is why drowning is so painful.
I almost drowned once, I literally gave up and floated to the bottom of the surf
it was painless, I was just set, I had no hope, didnt have a breath left in me, been underwater in the foam for over 2 minutes in the undertow and breakers
my shoulder hit bottom and I knew it was my last chance
I was in no pain
Agonizing way to go. CO2 buildup is why drowning is so painful.
I got CO2 poisoning while working in an underground pumped storage cavern. The CO2 had accumulated in the lowest point (was cleaning the turbine shaft seal at the bottom of the man-made cavern). Started feeling woozy so my co-workers got me up and out of the hole. On the ambulance ride to the hospital I remember the medic saying, "His eyes are rolling back in his head! We're losing him." Evidently, they "found" me by the time we got to the hospital. As far as I can tell, I'm still alive. :-)
BTW, no pain at all.
JFWIW.
I’ve read and been told that a single breath of high concentration CO2 causes a person to lose consciousness immediately.