Intervals Notification

Purpose

This is based on the HIIT principles of intervals:

1. Configurable warm up (maintain 70 bpm)
2. Max HR for time or distance
3. Rest for time, distance, or HR
   1. Example rest based on HR: be at 130 bpm for 20 seconds
   2. Watch would provide audible beep and vibrate
4. Configurable repetition of max and rest HR and/or time values