Auto-asphyxiation

[one_raven]

What happens when you suffocate long enough to pass out?
Let's say you had the self control to hold your breath long enough, or if you smothered yourself for long enough, to lose consciousness.

How long will the unconsciousness last if you weren't revived?
Will you wake up with a headache or some hangover-type symptoms (not an actual hangover, obviously, because you suffocated, not dehydrated)?
Could it do any permanent (or semi-permanent) damage provided that you don't crash down and break something?
What state of mind would you be in while unconscious? Similar to sleeping? Would you dream? Would you remember it?

On a related note...
What about other ways of forcing yourself into an unconscious state?
Such as doing that head-rush trick? (If you don't know, you stand bent over with your head down for a minute or so, then quickly straighten up to a standing position. If you do it right, you will lose consciousness. Good party trick )
How would the effects differ from asphyxiation?

 

[Carnuth]

you can also hyperventilate about 3 or 4 breathes while doubled over, then immediately stand up straight against a wall and press against the sides of the front of your neck, you'll black out with a warm tingly feeling and wake up on the floor.

 

[one_raven]

Oh yeah, I fogot to say that you have to take a deep breath while standing.
Something like that, I have never done, and only seen it done once.

Anyway, have you done that Carnuth?
How long were you out?
What effects (besides the warm tingly feeling) were there?

 

[Persol]

So how do you keep yourself from just falling and hitting your head at the bottom?

 

[Carnuth]

its a few seconds depending on how long and had you cut off the oxygen to your brain. my friends showd me how to do it, they usually did it to a person as a party thing for kicks a few times, then i figured how to do it to yourself. Basically its just like you fall asleep and wake up euphoric, i didnt cut of the oxygen too long so basically i just collapse slowly =)

 

[John Connellan]

I remember the kids used to do this all the time during yard-time in school (pressing hands to the side of the neck until unconsciouss). I never participated in it though cos I was always aware (even at that age) that it might do damage. Also, some of the teachers, on finding out that this was going on, actually told us the dangers of it.