Fat-Burning Heart Rate: What Is It, How to Calculate and Zones

Determining your heart rate zones is essential for planning appropriate workouts that help you meet your health and fitness goals. Your heart rate can tell you a lot about what is happening physiologically during exercise, as it gives you insight into what your body is burning for energy and if you are still utilizing oxygen efficiently. It also helps keep you safe while exercising because there is such a thing as overdoing it. Understanding your heart rate zones helps you determine if you are exceeding your body’s limits or not working hard enough to evoke change.

Heart rate training can be effective for fat loss when implemented correctly. This article focuses on the fat-burning heart rate zone, how to calculate it, and how to achieve it during your workouts. 

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Understanding the Types of Heart Rates

Your heart rate is influenced by several internal and external factors, including exercise, temperature, caffeine intake, nicotine use, medications, body weight, stress, and emotions. Understanding the different types of heart rates is essential for making lifestyle choices that optimize cardiovascular and overall health.¹

According to the American Heart Association, the different types of heart rates include:¹

• Resting Heart Rate: Resting heart rate is measured when you’re at rest and reflects your overall heart health. It usually falls between 60 and 100 beats per minute (bpm). However, the lower your resting rate, the better, as it means your heart doesn’t have to work as hard to maintain a steady beat.
• Target Heart Rate: Your target heart rate is measured during physical exercise and is calculated based on your age and maximum heart rate. Depending on your working effort, your target heart rate is usually 50% to 85% of your max heart rate. If exercise is new to you, it may be best to start in a lower-intensity zone and target 50% of your maximum heart rate. As you gain experience and strength, you might aim for the higher end of your target rate in the aerobic zone.‍²‍
• Maximum Heart Rate: Your maximum heart rate is considered the upper limit of what your heart and cardiovascular system can handle. It’s an approximate calculation that uses the standardized equation of 220 minus your age. For example, if you are 35, your maximum heart rate is approximately 220 - 35 = 185 bpm. If you are 20, your max heart rate is approximately 220 - 20 = 200 bpm.

Various healthcare professionals can help you measure your resting heart rate and calculate your maximum heart rate. From there, you can establish your target heart rate zones and work with a certified personal trainer to design individualized workouts.

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What are Target Heart Rate Zones?

Target heart rate zones are percentages of your maximum heart rate that fall within different aerobic or anaerobic exercise categories. There are five different heart rate zones, each corresponding to a certain intensity.³

Here is a heart rates chart to help explain each heart rate zone:

Zones 1 through 3 are purely aerobic, meaning the body uses oxygen to help burn fat stores for energy. These are typically moderate-intensity workouts with a lower perceived effort so that we can maintain the work for more extended periods, normally over 45 minutes.

Zones 4 and 5 become anaerobic, and the body no longer uses oxygen efficiently. Instead, we break down carbohydrates as our primary energy source so that our body can use the quickest system possible to create energy for these high-intensity exercise sessions and all-out efforts. Because these zones have us at our maximum effort, sustaining activity at these heart rates for longer than four minutes for Zone 4 and no longer than 40-60 seconds at a time for Zone 5 is not safe or helpful. It is also important to note that you should only train in Zones 4 and 5 for two to three days a week, while most of your exercise routine is in Zones 1 through 3.

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What Is the Fat-Burning Heart Rate Zone?

The fat-burning heart rate zone refers to a specific percentage of your maximum heart rate, or your VO2 max, where your body burns more fats for fuel during exercise. This is different from some of the other heart rate zones that utilize more carbohydrates for energy at higher intensity efforts. So, believe it or not, your body is using more fats at lower heart rates and intensities. Specifically, the fat-burning zone is typically achieved within Zones 1 through 3 or 50-75% of your maximum heart rate.

One recent study found that maximal fat oxidation occurs between 45 and 65% of your VO2 max. Now, it is essential to recognize that weight loss and fat loss are a product of a calorie deficit. So yes, burning body fat in the fat-burning zone is helpful; however, you must still exercise long enough to burn enough calories to be deficient.⁴

Here are some examples of the calories burned in 30 minutes based on various heart rate percentages (based on a 130-pound, 40-year-old female with an HRmax of 180 bpm).

Based on the formula3,4,5: Female: Calories/min = (-20.4022 + (0.4472 Heart Rate) - (0.1263 Weight) + (0.074 * Age)) / 4.184

Fat-Burning Theory 

The Fat-Burning Theory comes from the idea that different fuel sources are utilized at various exercise intensities. There are specific heart rates at which one will burn more fats and other heart rates at which one will burn more carbohydrates. Research shows that fat oxidation typically occurs during submaximal exercise or 45-65% of your VO2 max. Once you reach an intensity above that threshold, you are more likely to utilize more carbohydrates than fats to make energy.This is sometimes referred to as the cross-over point.⁴

Burning Fat vs. Burning Calories

Anytime you engage in an activity, whether exercise or simple daily tasks, you are burning calories. Your body requires energy to sustain baseline tasks like walking, breathing, and thinking, so you can imagine how exercise, which requires an elevated heart rate, burns even more calories. Still, burning calories does not always mean you are burning stored fat. 

When exercising at submaximal levels, you burn more fat than carbohydrates. However, the opposite is true during higher-intensity training. That said, regardless of what fuel source your body uses to create energy, you are always burning calories.  

3 Ways to Find Your Fat-Burning Zone

No two bodies are the same, so understanding how to find your fat-burning zone can be a game-changer for sustainable weight loss. Understanding your heart rate ranges can help you optimize your workouts and target fat loss more efficiently. There are several practical approaches to identifying your fat-brining zone, including:

• Get your metabolism tested.
• Try mild exercise routines.
• Use a heart rate monitor and the formula.

Once these methods help you lay out your heart rate zones, you can design workouts of various intensity levels to fit your fitness goals. These may include high-intensity workouts, strength training, and steady-state cardio.

Calculating Your Fat Burning Rate Zone

Research has found the fat-burning heart rate zone to fall around 70% of your maximum heart rate (HRmax) or within a range of about 60 to 75% HRmax.⁴ 

Calculating your fat-burning heart rate means first calculating your maximum heart rate. The easiest way to do this is to subtract your age from 220. So, if you are 35 years old, your maximum heart rate is 220-35 = 185 bpm. Then, multiply this number by 70% or 0.70. Your fat-burning heart rate is 185 bpm * 0.70 = 130 bpm. Here is a chart of fat-burning heart rate zones by age:

Fat-Burning Heart Rate Zone vs. Cardio Heart Rate Zone 

You may see the terms “fat-burning heart rate zone” and “cardio heart rate zone” used interchangeably; however, these are two different entities within the world of heart rate training. Remember, there are five heart rate zones to target with exercise, with Zones 4 and 5 being anaerobic (without oxygen). 

All zones can be hit during cardio-based and strength-based exercise; however, the “cardio heart rate zone” refers to the highest intensity (or highest zone) where you are still working aerobically (with oxygen). This is Zone 3 and correlates to 70-80% of your maximum heart rate. Cardio-based exercise and workouts within this zone have been shown to provide many health benefits, including weight loss, blood sugar control, lower blood pressure, and stress management.   

How does this differ from the fat-burning heart rate zone? The cardio heart rate zone is at a slightly higher intensity than fat-burning heart rates, and your body is thus required to use a little more carbohydrates for energy to sustain the workload. So, you will burn less overall energy from fats in the cardio heart rate zone than in the fat-burning heart rate zone. Again, a high fat-burning heart rate zone falls between 60-70% of your maximum heart rate. 

Best Ways to Achieve Your Fat-Burning Heart Rate 

The workout that targets your fat-burning zone may differ from everyone else’s, so it’s essential to know your resting heart rate, maximum heart rate, and target heart rate before choosing a suitable physical activity. Here is a list of exercises perfect for getting into the fat-burning zone, but make sure to track your heart rate while you work out!

1. Slow Jogging: Jogging is still a form of cardio exercise, but it should feel more manageable than actual running and is typically slower than six mph on average. You can do this outside or on a treadmill and take breaks as needed. 
2. Brisk Walking: Walking is one of the best forms of exercise as it is low-impact and easier on your joints than jogging or running. You can pick up the pace to increase your heart rate or find some hills to make the effort harder. Obtain the right number of daily steps for the ultimate weight loss plan.    
3. Cycling: Whether indoors or outside on your bike, cycling is another low-intensity exercise great for dialing in a fat-burning heart rate zone. If needed, add resistance or find a hilly route outside to increase the difficulty.  
4. Swimming: Swimming is a full-body workout that some people find more vigorous than others. Start with easy laps in a pool and take rest breaks between laps to keep your heart rate under control.  
5. Interval Training: You may be more familiar with high-intensity exercise (HIIT); however, you can keep this type of exercise in a lower-intensity fat-burning zone by increasing the rest intervals and reducing the difficulty of the exercises. A certified personal trainer can assist you in designing a HIIT workout to fit your needs.
6. Water Aerobics: Water aerobics can be a fun way to work out in a social environment while getting a great workout. It combines the resistance of the water with full-body exercises to help increase strength and cardiovascular endurance. 
7. Gardening: Fat burning can occur outside of high-intensity workouts. Many people don’t associate gardening with exercise, but it’s considered a moderate-intensity activity. Plus, you also get to spend time in the great outdoors, allowing you to soak up some vitamin D and fresh air.
8. Jumping Rope: Jumping rope is an excellent aerobic exercise that you can tailor to fit your fitness level. Start with a few minutes at a moderate pace and gradually work your way up to longer workouts as you get stronger.

A workout that targets fat loss should remain within 60-70% of your maximum heart rate and be performed for at least 150 minutes each week, according to the Physical Activity Guidelines for Adults by the American Heart Association.⁵

Try to include various activities to avoid burnout and engage different muscle groups. Here is a sample 1-week plan that includes cardio and weight-based fat-burning workouts:

Tools to Use to Measure Heart Rate

As mentioned, tracking your heart rate during exercise is crucial for maintaining safety and ensuring you hit your goals. Many devices, including watches, mobile phone apps, chest straps, and manual pulse checks, can help you track your heart rate at rest and during exercise. 

The easiest way to measure your heart rate is with a watch, app, or chest strap. You can check these trackers periodically throughout your workout to see if you are hitting 60-70% of your maximum heart rate and view your average heart rate for a single session. Garmin, Apple, and Fitbit watches all provide this data in real-time. Apps on your phone that track heart rate include Cardiio, Google Fit, Apple Health, and Cardiograph.

Chest straps tend to be more accurate than watches or phone apps. However, they can be more expensive and sometimes uncomfortable to wear. Examples of chest straps include the Polar H10, Wahoo TickrX, and Garmin HRM Pro.⁶ 

If you don't want to purchase an app or device, you can simply check your pulse and use a watch to calculate your heart rate. First, find your pulse just underneath your jaw or inside your wrist. Find the pulse and use a clock to count each beat over six seconds. Then, multiply this number by 10 to get your heart rate. 

6 Other Effective Ways to Lose Fat 

Reaching your fat loss goals requires more than just exercise, it requires a holistic approach that taps into several lifestyle factors. It is also important to note that fat and weight loss are different, so understanding which is right for you helps you reach your specific goals. Here are six other lifestyle habits to focus on outside of exercise if you need to lose fat.  

1. Keep Hydrated: Drinking water helps promote fat burning, and research shows that being consistently dehydrated leads to increased body weight.⁷ 
2. Focus on Whole Foods: Eating a balance of macronutrients (carbs, proteins, fats) and colorful fruits and vegetables is an excellent diet for general health and weight loss. One example of this is the Mediterranean diet.  
3. Go for a Slow and Gradual Weight Loss: Achieving weight loss too quickly can harm your body and lead to unsuccessful long-term results. A loss of more than 2 pounds per week is considered unsafe and may result in a loss of lean muscle mass.⁸ 
4. Mind Portion Sizes: Calories in vs. calories out is an important equation for successful weight loss. When putting together a meal or snack, be mindful of your portion sizes to ensure you consume fewer calories than you use. A registered dietitian can help you design a meal plan with appropriate portions to meet your needs.
5. Improve Your Gut Health: Research has shown a positive correlation between a healthy gut microbiome, weight loss, and reduced chronic disease, including diabetes, cardiovascular disease, and obesity.¹³‍
6. Keep Your Metabolic Rate in Mind: Your resting metabolic rate is the number of calories your body requires to function (i.e., breathe, pump your heart, fire your neurons, etc.). In addition, your body needs calories to perform daily tasks, such as cooking, cleaning, and moving about the house. Any calories burned beyond this will be the calories you burn for weight loss. Keep this in mind as you calculate your caloric needs.

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