Better for during anaerobic metabolism,its breakdown of glucose stops at an early point, producing lactic acid and two molecules of ATP.This anaerobic metabolism produces what's called an oxygen debt.
I never noticed a difference until I quit smoking to switch over to a vaporizer. And even then, the differences in my performance are almost negligible. For example, I do a 20 mile bike loop a few times a week and my times and speeds have not changed at all since I quit smoking. It still takes me about 70-75 minutes depending on the wind. I feel a hell of a lot better after a long cycle or run. My lungs are a lot less tight now. That's the biggest difference to me. Vaporizing definitely doesn't have a negligible effect on the lungs, you're still inhaling hot vapor but it's a hell of a lot better than combusted plant matter. I don't get that burnt out feeling with my vape either.
I run 5 miles a day 3-4 times a week and vap everday, even before I'm about to go run. Actually, I can't think of the last time I didn't vap/smoke before I workout. I found that my performance gets better everyday I train.
To throw my tuppence in, I used to do exercise while smoking but it started to feel like it wasn't good for me. This is just my experience but my lungs started to feel heavy and I'd get phantom sensations that were just worrying. So 2 1/2 years ago I made the leap to vaping and I've never looked back! I'd actually go as far as to say vaping weed is performance enhancing - on a long day's cycle it elevates me above any discomfort.