The target heart rate is your ideal heart rate, or pulse, during physical activity. Your target heart rate is within 50 to 85 percent of the maximum heart rate, which is the highest heart rate you should have during exercise. Determine your maximum heart rate by subtracting your age from 220. You can monitor your heart rate periodically during exercise by checking your pulse are the wrists, the inside of your elbow, the side of your neck and the top of the foot. To get the most accurate reading, put your finger over your pulse and count the number of beats in 60 seconds.