My biking app (cyclemeter) has an option to read data from the health app, so I set it to read and display my heart rate as I ride. Problem is, my heart rate wasnt working on on their app so I contacted them to advise of a bug. They confirmed it isnt a bug, Apple dont let 3rd party apps read heart data that has been provided by the Watch. Come on Apple, are you serious? Thats a massive amount of functionality that developers can't use and lost functionality for users.