I use an Edge 830 to record my cycling activities and the Garmin Forerunner 245 for my heart rate. I'm currently not happy with how they sync with another as my cycling activities from the Edge do not automatically sync to my watch. I've discovered to my dismay, that the only way to have my cycling activities visible on my watch is to open the Connect app and wait until my watch is finished with syncing with the connect app on my phone. Is your experience different than mine? I find it hard to believe.
I have not done any running to see if the converse also is no different.