Your heart is the most important muscle in your body. As you increase your physical activity, your heart will be working a bit harder, just like your other muscles. That’s why monitoring your heart rate is so important.

If you have a heart rate monitor: Just strap it on and read the results! If you’re measuring your heart rate by hand: Sit down in a quiet space and measure your heart rate by counting your pulse for one minute (alternatively, count your pulse for ten seconds and multiply by six, though this measurement may be slightly less accurate). To take your pulse, place your index finger and third finger on your radial artery (located on the inside of the wrist below your thumb).

Three Important Heart Rate Measures

1. Resting Heart Rate (RHR). The number of times your heart contracts per minute, measured when you’re at rest.
   
   

2. Maximum Heart Rate (MHR). The highest number of times your heart can contract per minute during maximum physical exertion. MHR is most accurately determined with a cardiac stress test, but for our purposes we’ll use the following formula: MHR = 220 – your age
   
   For example, the MHR of someone fifty years old is 170 beats per minute (220–50).
   
   

3. Target Heart Rate (THR). Between 50% and 85% of your maximum heart rate. As we increase your movement using non-planned exercise activities, we’ll check your THR to make sure we’re not raising your heart rate too quickly. Once you’re on pace and adding activity to your day, we’ll also use your target heart rate to maximize your cardiovascular fitness level.