Professional athletes and lay people have used heart rate zone training for years. It works. That’s why MyZone has been built around that zone training system to help anyone become better than they thought possible.

MyZone tracks fitness effort, rather than less accurate numbers like calories. The result is a tailored workout where an unfit person could do better in the rating system than an athlete, if they put in more effort.
…
Read full post here:
https://www.pocket-lint.com/gadgets/reviews/135834-myzone-tracks-fitness-effort-to-make-health-inspiring-again