If you don’t have a Myzone to monitor your workouts, you need to get one! I thought I’d only care about the calorie count, but I immediately found that the heart rate measurement energized my workouts! You can watch the fruits of your effort in realtime, and you can adjust on the fly to a range that best suits your goals. It’s a must have! I recommend a MZ-3 because it is USB charged and it has a memory. With MZ-1 there is no memory so your phone needs to always be at your side to measure your statistics.