Breathing your way to enlightenment

[lostmente]

A while back when I was in rehab I had some interesting discussions about a course someone did based on using breathing techniques to attain states of mind very similar to your traditional experience of tripping.

It's an ancient idea I know but I'm just blown away with looking back at my most hallucinogenic experiences and how my breathing patterns were preceding them.

Now when I re enact those patterns (and maybe this is just association) the state of mind returns.

it raises a few questions for me:

1. is 5ht-2a involved in respiratory patterns?
2. is tripping a form of oxygen deprivation?
3. how long can one go with limited oxygen without brain damage?