You don't suddenly conk out if you experience rapidl decompression at 37K, you have a (small) period of useful consciousness followed by a period of (I suppose) 'useless' consciousness before you finally expire (assuming you are not hooked up to appropriate oxy). You could hold your breath - but you can't hold the same mass of air in your lungs at 37 K as you would at SL, you could try, but you'd prolly blow up.
If you do a Google search for hypoxia, Rapid Decompression and the like then you'd most likely find a bunch of gen. I am sure there are a bunch of people who know much more about this subject that I do that will respond to this question - I just know from experience, I don't know the whole medical shennanegons about it.
If you go through (most countries) mil flying training, you get the delight of experiencing the decompression chamber. This fun machine can simulate RD and you can experience hypoxia and horrendous stomach cramps cos you didn't follow the advice to avoid the beer and curry the night before.
Cheers,
MT