Great work, congratulations! And thank you.
Something I would love to see is time spent in HR zones per week, month or any period chosen. I see you already have it per exercise and you say the athlete will be able to configure his own zones (an absolute must). It will be great if this can be expanded to any period of time, or at least per week. It is amazing how little exercise data programs/apps can give you this simple but very handy functionality.