This is a test of commonsense. Complete the next sentence:

How to control your treadmill workout using your heart rate
Take your pulse.
If you don't have an individual heart rate monitor, you can take your pulse to determine your heart rate. To find your target heart rate, you must first determine the number of times your heart contracts (or " beats ") in a minute while you're at rest.
First thing in the morning is the best time to measure your resting heart rate. At other times during the day, your heart rate may differ in response to other activity.