I was going to search for a thread on this very subject. After a really long ride my lungs burn real bad. They might have always done that, but for some reason I'm just now noticing how after a ride, the feeling continues on for a while. When I was in Colorado in June I rode a lot, and that was hard for me because I am not acclimatized to altitude. However, there was no burning lungs there. just here, in South Central Michigan. What gives?