How to make sure one of Apple Watch's key health features works

In addition to providing notifications, the Apple Watch is also supposed to be a powerful fitness and health gadget designed to both motivate you and record a variety of parameters related to your daily activities and workout sessions. One of the things the Watch can record is your heart rate, and Apple has put together a special page on its support website that details how the sensor on the back of the Watch works and how to get better results from it. DON'T MISS: How to install 'Netflix for pi...