Do it.

It certainly can't hurt you to exercise.

I'm not sure how much it helps keep your lungs healthy, but I smoke as much or probably more than you do, and I run a few miles every single night, as well as play basketball, and my lungs and I feel great. Never had a smoker's cough or anything.

Just do it, man. Regular exercise makes you healthier in your body and your mind.

Plus, there's nothing better than finishing a 3 mile jog off with some fat bong rips. :smokin: