So I read that it was possible to hold your breath in a lucid dream and cause your sleeping body to stop breathing. Do you think it would be possible to hold your breath for so long you pass out or maybe even kill yourself?
Sorry if this is a little morbid, I’m just curious…
Your sleeping body (Astral body) doesn’t have lungs and doesn’t breathe physical air to maintain itself. It breathes only pure non physical energy, vital energy, chi, this breathing is executed by the entire body and not by a specific organ so I doubt you can stop it at will, you can slow down or speed up the absorption, which by the way, can be done in the physical plane as well. therefore I don’t think that holding your breath will cause anything. Notice you can breathe while plugging your nose… (so what exactly are you breathing?)
You don’t physically breathe in a dream. Any inhaling/exhaling actions of air (or whatever it is) you do or believe you need to is a result of your thinking patterns which are caused by the earth life. Any consequences of “not breathing” in a dream will also be subject to your beliefs.
Nonetheless, or more accurately, therefore, it should be quite interesting to try it.
Ill let you know how it went
By passing out or killing yourself, you mean your physical self/astral self?
I doubt it, just from what I’ve read… being able to hold your breath forever in a dream is news to me, on the contrary it sounded like a dream sign to be able to breathe under any and all conditions: underwater, pinching your nose shut, during an autopsy where you can see your lungs being removed and set to lie in a metal pan, or having had a DC blast a cannon ball through your chest and then peek his head through the hole to taunt you about it, etc. (Okay, I’m getting morbid. 
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The sleeping, physical body takes care of itself.
I would doubt that the physical body would allow such a thing to happen unless there was something seriously wrong with it’s normal functioning. If you held your breath in a dream, and it carried through to real life. Your normal reflex reactions would kick in, you would get an adrenalin rush, and your panic reflex would activate. (It takes considerable mental focus and determination to override these reactions.) The reaction would undoubtedly wake you up, if it didn’t cause you to stop holding your breath in the dream. 
That’s of course assuming it carried through to reality in the first place.
Observing a sleeping cat you can notice that when it is in REM sleep it will sometimes breathe faster than normal while twitching. One imagines it has an intense dream. The breathing is influenced, clearly. I would guess that if you do stop breathing, you would wake up soon. Passing out while asleep seems like a strange thing.
You can’t die from holding your breath. You may fall unconcsious but you’ll never die.
But you’re already unconscious!
I think you’d just wake up. Your subconsious would either wake you up immediately or make you stop dreaming.
You want to start a discussion on this? 
In any way, when you are sleeping, the body’s mechanisms are still operating. After all, if they weren’t, you won’t really be breathing at all, won’t you? even if you do physically breathe by breathing in the dream, you dream for a very small amount of time during the night.
Just like breathing automatically, the body has many many more mechanisms. Our , and every other living creature, strongest instinct is the survival instinct. Without considering very very exceptional cases (such as monks truly beyond the physical illusion burning themselves, which is of course, very rare), this instinct will have the last and strongest impact on every living creature. In every situation, we strive to survive. The body’s mechanisms for operating in accordance to this instinct are very strong. It is impossible for any living creature, except for humans under very specific conditions, to hurt itself. It’s way beyond logic and conscious thinking. I have friends that wanted to hurt themselves badly for reasons I will not explain at the moment, and simply couldn’t do it. They were praying something will happen but couldn’t do it themselves. Suiciding is very very hard. Even for people at an enormous mental distress. Going against those mechanisms is almost impossible. According to already being unconscious, passing out is impossible, so the question is if you can die. Not breathing in order to get killed = suicide, which as I said is nearly impossible of course. If you just do it for fun, the body’s mechanisms will of course never allow anything near dying. So, if you just stop your breathing in your dream to see what happens, you will never get killed.
You can’t kill yourself by mistake, no matter what. you have to really want it and then go against your instincts, which is hard.
Trying consciously to stop breathing in a dream in order to get yourself killed is probably possible… Everything is 
It’s probably a very difficult way of killing yourself though… and in any case, the breathing in the dream isn’t necessarily connected to the physical breathing. If you stop breathing in the dream, there are many options, maybe your body will keep breathing, maybe you will wake up after a few minutes, maybe you will fall into deeper sleep, hard to tell and probably depends on the person, but anyways to stop breathing while dreaming is to physically stop breathing of course…
Just like rolling in your dream doesn’t make your body roll, same goes for breathing… I am sometimes able to be highly aware of my physical body to the extent in which I can decide to roll in bed, so in this way, it is probably possible to command the body to stop breathing, although the mechanisms will work rapidly against you, making it much much harder.
Never had any issue with this, I could hold my breath in an LD for an hour and not have any issues with my actual body. How you breathe in a dream doesn’t generally influence how you breathe in real life.
Yes, that sounds about right. For many people breathing is so instinctual that what they do in a dream isn’t going to effect real life. While we do send nerve impulses while dreaming to perform dreamed actions the REM paralysis prevents these actions from actually being carried out.
Very Small? the average person who sleeps 6+ hrs spends anywhere between 2-4 hours dreaming which is like 25-40% - not that small in my opinion.
I meant to show that the body can breathe without you breathing in the dream otherwise it wouldnt have the necessary air throughout the night.
I dont think we even breathe in dreams, Ive been flying in vacuum without getting hurt. Your astral body cant breathe and the only obstacle to hold the breath is that we THINK that we breathe. If you get nervous enough in a dream you will wake up, the consciusness is programmed that way.
Honestly, im unsure about the whole holding your breath and dying idea… but you can never be too sure. About two months ago I had a dream that I had taken some kind of odd drug (that to my knowledge i think contained strychnine, which causes muscle contractions and spasms, along with a clenchy feeling)… this being a just a dream you would think that it wouldn’t do anything, but i felt an actual strain on the muscles in my jaw, and my left canine teeth were clenched together, just those two, which was extremely painful. I tried to relax my jaw in the dream, but I kept drifting back into that clenching takeover feeling. Eventually I woke up and my jaw and teeth were totally sore, and still felt somewhat clenchy… on top of that my teeth were chipped
that’s has got to mean something. I know that our minds have a very strong control over the body.
Well, entirely unaffected from the dreams were not. For example: If you fall down and wake up by the slam, you feel a little pain (it disappears fast though)
Some of my dream are affected by RL-things, but its rare
One time, I was in a LD, and as I was waking up from it, I was eating a donut that I called into my hand with my magic LD powers. I ate the donut, and when I awoke, to my surpise, I was still tasting the donut for about 20 seconds after. 
check out figure 3, experiments show that dream respiration really does influence real respiration. I think that if you were to hold your breath THAT long, you’d automatically wake up though, just like your body doesn’t let you hold your breath that long in waking life.