Each day using my biostrap becomes more and more intuitive. It also seems that the biostrap is becoming more in tune with my biometrics. In the beginning I had my doubts. I was concerned about calorie calculation. I have an iFit chest strap heart rate monitor which is paired to my BioStrap. In the beginning, I was still running my Zephyr heart rate chest strap connected to sportstracklive along side the iFit and BioStrap. I was seeing wide gaps between calculated calorie burn at the end of my workouts in the Biostrap. Now running the Biostrap with the iFit heart rate monitor by itself the calorie calculation seem to be more in line with what my perceived rate of exertion and calorie burn should be.