By Ann OlsonYou've probably heard that your fat-burning heart rate zone can help you burn off more fat--but what exactly is it? If you think it's just the measure of your heart rate, it's not--nor is it how much your heart beats at its maximum. Your fat-burning heart rate zone is actually 75 to 85 percent of how fast your heart beats as its maximum, which provides the perfect environment for the body to burn off fat. For example, if your maximum heart rate is 200 beats per minute, your fat-burning zone is 150 to 170 beats per minute.Its benefits aren't only superficial, however: exercising in this target zone has been shown to strengthen your heart muscle, reducing your risk for cardiovascular disease. A stronger heart also means you'll find it easier to do other physical activities withou