Answer:
с. 60-80% of your maximum heart rate
Step-by-step explanation:
The "target heart rate" is very important when you want to know how to do your exercise properly without straining your body or relaxing too much. In order to do this, you have to get your "maximum heart rate" first by subtracting your age from 220. The difference will be multiplied by 60% to 85%, depending on the exertion level that you want.
For example, your age is 20. You have to subtract 20 from 220 and that will give you a maximum heart rate of 200 beats per minute (bpm). If you want a 60% exertion level, your target heart rate is 120 bpm (200 x 60%).