Answer:
147 to 161 bpm
Explanation:
The appropriate formulas are ...
220 - age = maximum heart rate
⇒ 220-32 = 188
Maximum heart rate - resting heart rate = heart rate reserve
⇒ 188 -52 = 136
(Heart rate reserve X training%) + resting heart rate
⇒ 136 × {0.7, 0.8} +52 = {147.2, 160.8}
John's target heart rate range is 147 to 161.
