I had childhood asthma, and while I'm not bothered much by it now, my lungs are pretty scarred. So smoking generally took a lot out of my breathing. Made me a night smoker only. This afternoon I vaped about 1.5 cigarettes worth, then went on a two mile bike ride. No problems at all. Well, my legs got tired pretty quickly, but that's most likely because I haven't ridden in about a month. Thought this information might be helpful to those looking into e-cigs that are apprehensive towards the claims that people can breathe easier. I was skeptical too. Not anymore.