It all depends on you. I knew people in high school who smoked regularly and still ran cross country, track, and participated in other sports quite successfully. I doubt there's any serious permanent damage to your lungs because of the smoking. If you get back on your exercise routine and start working out like you used to, you should be able to pick up all or most of what you used to have. I was in excellent shape all throughout college. My exercise routine used to be this: run 4.1 miles per day, lift 45 minutes rotating upper and lower every day, and then play a few games of basketball. Getting away from the college routine, work, and other things have gotten me far from that condition; I can barely make the run, and that's all I do. I'm working on it now, and I hope to be back in college-like condition by late spring.
So just keep at it, don't let the prospect of what smoking may have done to your lungs keep you from trying to get back into your previous shape. You'll get there eventually.
