Re: Decrease in lung capacity
+1 on psychological.
But it may be that NO exercise mixed with hookah might cause more rapid decreases in breathing??
All i know is that i've been smoking pretty consistent for 2 years, and these past 6 months or so have been 3-4 bowls daily and i still get large pulls and can STILL exercise and play tuba/trombone as well as before.
soo.... start exercising? if not for the hookah, then for your health haha.
and if you have a hard time running, try doing low weight strength training... see a physical trainer, they are LOADS of help. i promise.