Choking someone out is essentially starving the brain of oxygen or cutting off the blood flow. It’s medically different but with similar results. Like with a concussion, you can come out of it okay.
The problem is that this gets treated as an easy and convenient “no kill” solution in a lot of fiction. Where, it really isn’t. Also, the longer they’re out the more likely it is something has gone wrong. I mean, you knock someone out with a choke, stuff them in a closet, and they’re still out when you close that door? They’re probably dead.
It’s very difficult to get someone to stop breathing. It’s also very difficult to tell where the line is between unconscious and dead. Some chokes like the ones that cut off blood supply are very quick, it’s easy to hold it too long. When practicing these kinds of martial arts for safety reasons, you tap out the second you start to feel it and it’s your partner’s responsibility to let go when that happens.
It is dangerous.
The trouble with a lot of fictional fighting is that there’s a desire (an understandable one) to want to make it “safe”. To say that there’s an easy determining line where “this won’t kill them but that will”. That there’s a safe way to do it that will lead to a happy conclusion where the character doesn’t need to bear the brunt of hurting other people. Films like some James Bond movies, other action movies, Saturday Morning Cartoons, present this idealized state where so long as the character doesn’t kill anyone else then they get to remain a “Good Person™”. This often leads to weird, unironic moments in fiction where the main character is doing straight up terrible things to people such as crippling them for life i.e. “Disabling shots”. While the narrative pats them on the head for being cruel and unusual while the villain is just straight up ending people’s lives.
There is no line. It is all gray area.
Choking someone out, asphyxiating them is denying their brain the oxygen it needs to function to the point where they pass out or die. That is what a traditional choke does. It starves the brain of oxygen. Starving the brain of oxygen can result in permanent damage. It can turn you into a vegetable, it can damage functionality and can leave long term issues even if they live. Starving the brain of any resource it needs to function will kill you. The good news is that when it comes specifically to air, it takes a while.
The point of the choke when you’re not trying to kill, in a lot of ways, is to scare them into giving up so they’ll stop fighting. If you get them to the point where they pass out, there is a good chance that they’ll never wake up again or that you did permanent damage to their brain.
There’s a basic understanding that I feel is hard for people to grasp when it comes to writing fight sequences in fiction which is: your character is going to hurt somebody. For some of us, this obviously trips up the part of the brain which goes “but if my character hurts someone, doesn’t that make my character a bad person?” which is a natural reaction to have. The secondary question comes: “does that make me a bad person?” because we often relate to our characters.
The answer to that is no. Your character comes from you, but they’re not you. It is okay to have these thoughts. It’s okay to think about killing people, so long as it stays in your head or in a fictional space where it belongs. Writing any character who fights is, on some level, crossing over into the realm of questionable morality.
Violence creates uncomfortable questions that we have to ask, both about ourselves and the human condition in general. They don’t come with easy answers. Trust me. Some of the greatest philosophers in human history have mulled over these questions and failed to find satisfactory answers.
Not being able to answer them is okay.
And not running away from those questions will make you a better writer. Lots of characters are going to ask them and the answers will be different each time, they may even differ from the ones you found for yourself.
At the end of the day, violence is about causing pain to someone else. It’s about harming them. You can justify it to yourself. You can understand the situation. You can review it over and over again. But, at the end of the day, that’s what it is.
Accepting that is probably the first step to writing really good fight scenes.