I have been doing the Firm's Cardio Tapes with 8 or 10 lbs dumbells and have no problem staying in my target heart rate zone and I do not feel any pain. I am doing CM with 5/8 lbs and therefore I am considering it a cardio tape because it does not build muscles. If I am using a weight tape the next day I am using a lot heavier weights and do more push-ups. So why can't CM be just a Cardio Tape?