The heart rate that's not measured, but calculated, is called the . target heart rate
maximum heart rate
resting heart rate
ATP heart rate

It’s the target heart rate! hope this helps!

This is first hand knowledge, top-level athletes, successful business people and achievers in all fields all  set goals. setting  goals  gives you long-term vision and short-term motivation . it focuses your acquisition of knowledge, and you to organize your time and your resources so that you can make the very most of your life.