You've determined that Ben should be working at or above 80 to 90% of his maximal heart rate. He's 21 years old.

Calculate Ben's training target heart rate and then tell me which option shows the correct range:


a. 120 to 137 bpm
b. 159 to 179 bpm
c. 180 to 191 bpm
d. 200 to 225 bpm