i am thinking the people that hold it in for long periods of time are either thinking they are gonna absorb twice the amount as only holdin it for a few seconds or its a macho thing. everytime i see someone doing the hold in and choke thing on purpose im thinking, what a douche, in my head. most of the effect u will have from holding it in is from oxygen deprevation and instead of oxygen u got smoke,but damn right thats gonna make the smoker lightheaded and add to the high effect tho.definetly more likely to lead to chronic cough. ya dig? :stoned: .