Analyzing your heart rate zones is a great way to ensure your easy runs stay easy, and your hard runs are pushing you enough.
How to check your HR zones:
Open the URUNN app and tap on your completed run to open its details.
Select the Charts tab from the top menu.
Scroll down past the main Heart Rate graph to the Heart rate zones section.
Here you can see the exact breakdown of how much time (and what percentage of your run) you spent in Zone 1, Zone 2, and higher.