Thats what I figured. Im a little out of shape, but I beleive my heart-rate gets so high because of one, I do pretty intense cardio and two, Im on a ECA stack. Ill lower my intesity and pro-long my time, thanks Mr.X. What is a good length of time to do max cardio w/out becoming catabolic? I dont want to lose muscle! BTW I use a stationary bike for my cardio needs, 3-4 times a week.