I am a 49 yr old female, 5'6, 218 lbs, very sedondary. I climbed 4 flights of stairs the other day and my heart felt as though it was going to burst from my chest, breathing was very labored and short, I have felt sob from physical exertion before, but never to this degree! I thought I was going to pass out. My colleagues told me to sit and rest. I did not do that, but after walking slowly for about 5 minutes and then resting I was ok, Pride, did not want to fall out in a cafeteria full of doctors. After about 5 minutes, I was ok. This episode really scared me!!! Could it be PH, did I have a mild heart attack, stroke?