Apps Heart Rate Zones with Apple Watch

[Burnstd]

I currently use a Fitbit surge to track my runs, but I sometimes also wear my Apple Watch because I like to have pace on one and heart rate on the other. During different runs I target different heart rate zones depending on what I am aiming to accomplish that day. I am looking for an app that will vibrate or otherwise alerts me when I fall out of a customized heart rate zone. Any ideas?

 

[Mad Mac Maniac]

A tricky part about your request is that your iPhone needs to be unlocked to access HR and send notifications. HeartWatch does something like that, but I don't think it's completely customizable... You can set alerts for customizably high resting HR readings, and I've noticed that I also get some notifications during workouts, but it seems to be a different threshold and I'm not sure how to trigger that.