So I'm 20 and seem to be pretty regularly hitting 180+ for a heart rate and hit 190 today. Seems a bit high (200 is supposedly the upper limit for my age group). Should I be overly concerned? Maybe kick down the work out a notch? It just seems strange to me, because today I hit 190, but wasn;t even out of breathe. Thought maybe the heart rate monitor as broken, but I checked my pulse manually and it was defiantely up there...