Without meaning to argue with anyone or start a flame war, I've found that I also get higher when I hold the smoke in for 10 seconds or so versus instantly exhaling (any longer than 10 seconds for me doesn't really increase it though). I've tried on several occasions to prove myself wrong, as I have seen the studies, but I never get as high when I don't hold it in. If I'm still wrong about it, at least I'm high :stoned: