I've put together a Data Field that gives the recent history of the Heart Rate (1 minute default, but configurable).
The idea is to give a simple view for monitoring ones Heart Rate and making sure that one stays within the Aerobic Heart Rate Zone that one's targetting for the run/training.
I tried to keep the design simple, so that a stupid brain (during running) can understand it without having to think too much or look too long.
It's available here and can be added to any activity:
https://apps.garmin.com/en-US/apps/f6f3f163-7e53-40f0-8201-b4b1b2eb8cf9
Have a look at it and please try it out
Hope you enjoy! Keep it green!
Viktor