Monitoring Heart Rate During Exercise


I am looking for an exercise app for the Apple watch that provides specific functionality. I had some medical testing completed recently that identified optimal ranges for my personal heart rate for different types of exercise goals. I have a heart monitor, but I need to find an app that lets me enter the range I want my heart rate to stay in during exercise and then have it tell me (via vibration or sound) when I either am in that range or I am out of that range.

For example, if I need my heart rate to be in the range of 120-124 beats per minute during exercise, I need some way for the watch to let me know when I have reached that range and let me know when I leave that range so I can adjust my pace to try to remain in that range during my exercise.

Is there any accessible app that does this?