Gotta agree with those that are saying that being physically fit or unfit is a big factor in it. Of course the inhalation of anything besides air isn't the best thing for your lungs, but as a physically fit person who hasn't smoked a cigarette for a couple months, yet I have smoked sizable amounts of cannabis, I am comfortable saying, my lungs are doing extremely well and I rarely get out of breath any more.

High altitude hiking can be pretty rough on a physically unfit person by the way. Did some hiking in Colorado as a cigarette smoker, most unpleasant hike I have ever done had more fun in the Bisti Badlands in NM lol :thumbsup: