Its been awhile since I did any kind of training on drowning, but you can drown and not die. What happens is the body goes unconscious, has the inability to get out of the water and that is the act of drowning. Drowning does not always mean death and when you see in the movies when someone pulls another person out of the water, and they only cough up a mouth full of water and come back to life, that can be accurate. I witnessed that a few times, once with my little brother at a pool when he dove in and hit his head and went unconscious and I dove in and brought him up myself. My friend pulled him out of the water, I actually smacked him across his face (we were kids) and he coughed a couple times and waaa laaa he was back to life. Just like you see in the movies, but scared the fook out of both of us.
What happens is the trachea just closes off completely, just like with eating. When you eat food, the body recognizes it doesnt want this substance in the lungs, so the trachea closes and only allows food to go down the esophagus, otherwise we choke on food and cough and in extreme cases need heimlich maneuver. When this gets lazy (generally in old age) we call this dysphagia and in extreme cases of dysphagia, one can aspirate and die. Same concept for water, body recognizes it is in trouble and cannot get air due to being under water and the body will shut down and go unconscious. When this happens, the trachea closes automatically as well. Dont ask which nerve controls this, but its on the autonomic function and its somewhere in the brain. The person is not dead yet, and it is not fatal until the body relaxes and the trachea opens back up and water goes rushing into the lungs. Its been found that the body will hold the trachea air tight and unconscious for quite some time (cannot even guess at this anymore) but people have been saved under water and had anoxic brain injuries due to lack of O2 before the trachea actually opened and allowed fatal drowning. Just kind of tells you how long the body can hang on under water without actually dying.
You can see this a lot if you watch the documentary "The Deepest Breath" on netflix. Its about the deep diving sport and when they dont quite make it to the top, they are ghostly gray and dead looking. The spotter will just push a breath into their mouths, and all they are doing is tricking the brain to reopen the trachea because it recognizes it can take a breath of fresh air again. They hold the person up for awhile and they eventually wake back up and start breathing again. But technically, when they go unconscious, they drown lol.
