I m wondering what a medical definition of shortness of breath would be??? ...or, better yet, at what point should I be concerned? I m 70, very active, still build decks, run wheelbarrows, seem to be okay really... but sometimes as I stop to catch my breath, I wonder at what point I should be worried. Or if i should be worried??? I always can keep going after catching my breath, again, just curious. Thanks, Garry