For years, I get very sleepy at times when (trying to) exercising. It's isn't low blood sugar, but nearly narcoleptic - I feel like I need a nap.
I can manage moderate exercise, but climbing stairs or a hill really gets to me. One time I nearly didn't make it out of a canyon hike.
I am new to this site, and also have not yet confirmed a diagnosis (my mother died of COPD), but the more I read on here, the more I see I need to learn even more!