First of all, this watch is incredibly difficult to set up. The operation guide is hard to understand. Secondly, it is also very difficult to press the heart rate buttons on the right hand side while you're working out. The manual says to hold the buttons down for 5-7 seconds, however, I find myself having to hold the buttons down for 10-15 seconds sometimes. Even worse, after 15 seconds of holding the buttons down, it won't even give me a heart rate reading! So, I would suggest not wasting your money on this worthless product.