Stupid question about cardio??? Most people say that your heart rate should be at 60-70% when doing cardio. Ok, what exactly soes that mean? 60-70% of what? How would you monitor if you are at 60-70%??? Do the little bars that you put your hands on on most traedmills help? Can you use that to tell?? Sorry for the syupid question but I just wanted to know! Thanks bro's!!