Fat-Burning Heart Rate: What It Is and How to Target It

If you exercise because you want to lose weight, you've probably heard or been told that, for the best results, you should work in your "fat-burning zone." Your fat-burning zone refers to the workout intensity that gets your body to burn primarily fat for fuel and is often measured using heart rate.

Fat Burning Zone

The fat burning zone refers to a target heart rate that requires more of your body's fat stores to maintain. The fat burning zone is typically between about 50% to 72% of a person's VO2 max. Although this zone is called fat-burning, it doesn't mean you will actually burn more fat than if you worked out at a higher or lower intensity. Fat burning zone theory does not take into account the effects of more intense exercise or length of time spent working out.

Target Heart Rate Zones

Your resting heart rate (RHR) is the number of times your heart beats per minute (BPM) while at rest. You can determine this rate by placing your index finger on your your wrist or neck and counting the beats you feel for 60 seconds. A healthy RHR is usually between 60 to 100 BPM.

Your maximum heart rate (MHR), or the maximum number of times your heart can beat in a minute, is calculated by subtracting your age from the number 220. For example, if you are 30-years-old, your MHR is 190 (220 - 30 = 190).

When it comes to exercise, particularly cardio exercise, there are different​ heart-rate zones that equate to different levels of intensity. These levels are based on MHR and determine which energy systems your body uses during exercise, directly affecting how many calories you burn.

Fat-Burning Heart Rate

The fat-burning zone is the lowest intensity. Why? Because the body relies on more stored fat (versus carbs) as its primary fuel source when you work at a lower intensity compared to a higher intensity.

Some people have translated this to mean that you actually burn more fat when you work at a lower intensity, but that's a bit of a misconception. In reality, picking up the pace will torch more total calories—and ultimately more fat—in less time. And it's the number of calories you burn overall that leads to the most weight (and fat) loss.

To give you an example, the chart below details both the total calories and the fat calories expended by a 130-pound woman during cardio exercise. As you'll see, the woman burns more total calories and more fat calories when working out at a higher intensity.

Now, this isn't to say that low-intensity exercise doesn't have its place, especially if you're just starting out and can't sustain a faster pace. If you go slower, you may be able to exercise a lot longer, so you'll end up burning more calories and fat that way. 

Even for more advanced exercisers, endurance workouts should be a staple of a complete fitness program along with short, high-intensity interval workouts. Interval training where you alternate high-intensity exercise with low-intensity recovery periods is proven to increase fitness and burn more calories than steady-state cardio.

Structuring Cardio Workouts

If you want to lose weight, a general cardio schedule would include workouts at a variety of intensities within your target heart rate zone. For instance, if you're doing five cardio workouts a week, you might have one high-intensity workout, one lower-intensity workout, and three somewhere in the middle.

Low intensity cardio helps you build more stamina because you can work out for longer periods of time. This, in turn builds endurance and increases the amount of calories you burn overall.

A beginner cardio program lets you slowly build endurance while getting you a bit out of your comfort zone. That way, you don't have to spend an entire workout miserable, yet you'll still challenge yourself, which will burn more calories. Below is a sample program that will help get you started. 

The key is to start with what you can handle and slowly build from there. If you're just getting started, don't worry too much about how hard you're working. Focus more on making exercise a habit you can manage on a regular basis.

Other Factors to Consider

Exercise is not the only way to burn excess fat. You can also get your body to shed fat by eating a balanced diet, watching your portion sizes, drinking plenty of water, and getting enough sleep. The more avenues you use, the faster you drop the extra weight.

Plus, burning fat or losing weight is not the only goal of cardiovascular exercise. Working out regularly has been found to lower your resting heart rate, which also reduces your risk of dying early from cardiovascular disease.

A Word from Verywell

Everyone's fitness level is different. Additionally, certain medications can affect a person's heart rate. Therefore, before beginning any new workout program, you should consult with your doctor to determine whether that exercise is safe for you and, if it is, what your goal heart rate should be.