To do this, use your index and middle fingers to find your carotid artery in your neck. Count the number of beats during a 10-second span and multiply that number by six. Do this for three days in a row. Then add those numbers together and divide by three to get the average. This number is the resting heart rate that is unique to you.
Olympic athletes tend to have lower RHRs than couch potatoes.
So if you feel yourself getting into better shape as you train, you should recalculate this every few months or so. The first part of Karvonen's Formula produces a number that is your heart rate reserve. These target heart rates are your goals while exercising. To burn fat, I should train at 138 to 151 beats per minute. To work my heart, I should train at 151 to 164 beats per minute.