Re: Decrease in lung capacity
I have mild asthesma (never needed any meds, but still hurts like hell when I run more than a mile) and smoke hookah daily. I still can draw just fine after a few years of smoking, lift weights 4-5 days a week and am fine.
Of course, ANY type of smoke isn't good for your lungs. But, I think any idea you have about decreased breathing ability is purely psychological.