Hey guys - two main issues with the app for me.. several times when doing a session, if I leave the app briefly during a 3 minute rest period say to go into Spotify, the app stops the interval session and basically resets itself. the heart rate connection is absolutely rubbish. It does not in any way reflect the actual heart rate in a constant manner. For example, I got my heart rate to 160 beats per minute, during the rest period I lowered it to 130 beats per minute for say two minutes but in the app, it is still showing the 160. Hope this helps