I currently use a Polar Heart Rate Monitor (HRM) when I am exercising and considering using the Apple Watch instead to monitor HR. I have not read much about the technology that is uses to communicate with other devices and apps. I tried the Fitbit and it did not communicate with any equipment in my fitness center like the Polar chest strap. Also it did not work with my fitness app "Digifit" which supports Bluetooth Smart, Bluetooth Low Energy protocol. How about the Apple Watch?