Its very well made app. But I cant use it because average HR readings taken from apple watch are calculated wrong. When apple watch is in workout mode it takes much more HR readings than when no workout is activated. This app calculates average based on totals amount of readings divided by number of readings. So if your regular HR rate is around 60, then you go and do workout for 1 hour at 100+ bpm, your average would look like 95 (like you about to have a heartattack). Time should be weighted in the formula, so Average for day should be actual average as if apple watch takes same amount of readings per hour in workout and regular mode. I tried to contact developer, but could not find an option on web-site. Please correct this error and I would gladly rate 5-star.