Thank you all for responses... I do take cycling classes 3 times a week, one double class. What I noticed is that when my cycling instructor says she has 80% mhr, I usually have about 82-85%. Not sure if it's good or bad, maybe she has different resistance on her bike, maybe she is using her VO2 better, who knows.... I know that on my sprints i go to about 92-95% and that I think is pretty good according to some info i found on net. All in all , my average is about 75% for a cycling class.