What Is Your Fat Burning Heart rate? (And Does It Work)

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Some people claim there is a fat loss heart rate when exercising, a heart rate for optimal weight loss. How much is it and is this a myth or reality?

If you’re looking to lose weight this fat-burning heart rate sounds like a great concept that helps you get more out of your workouts. There might be some truth in the fat burning heart rate but is it also actually the best thing to focus on for weight loss?

What is the fat burning heart rate?

Your heart rate is the number of times your heart beats per minute. How many times your heart beats depends on multiple things like activity levels, gender, weight, genetic factors,… Your heart rate is usually a good indicator of how intense your workout is for you.

Notice the “for you”. For example an elderly, inactive lady might be doing high-intensity exercise by climbing stairs while a professional athlete has to sprint to get high-intensity exercise.

In general, when someone is just sitting down, a person’s heart rate is between 60-100 beats per minute. Your heart rate when not doing anything is considered to be your resting heart rate. These numbers are a fairly flexible estimation. For example, if you exercise a lot, chances are your resting heart rate is lower than 60 beats per minute.

Being outside these numbers is no reason to start panicking just yet but you might want to talk about it with your doctor.

When you exercise your heart rate goes up. The more intense the exercise the higher.

The fat burning heart rate also known as the weight loss heart rate is the intensity zone at which your exercise burns the most fuel from fat instead of fuel from carbohydrates.

How to calculate your fat burning heart rate

There are 2 simple steps to figuring out a rough estimation of your fat burning heart rate.

Maximum heart rate

The first thing you have to figure out is your maximum heart rate. The maximum amount of beats per minute your heart can handle without shutting down.

You can get an estimation for your maximum heart rate by subtracting your age from 220. For example if you are 50 years old, your maximum heart rate would be about 170 beats per minute. The actual number is highly dependent on your activity levels and other factors.

The supposed best heart rate to burn fat

The fat burning heart rate is between 50 and 70 percent of your maximum heart rate. Again for the example of a 50 year old person that would come down to between 85 and 119 beats per minute.

This specific number known as the fat-burning zone is a thing because at that heart rate you burn the most amount of fat during your exercise. It’s the tipping point between aerobic (cardio) and anaerobic (high intensity) exercise. When you start going over this rate your body starts to use energy from other sources like for example glycogen.

Target fat burning heart rate chart

This can be summarized in this target heart rate for weight loss by age chart. Keep in mind that a lot of other factors determine exactly what your heart rate should be. In reality this is a very individual thing (1).

These numbers are very rough estimations but they give you an idea of where to start.

Does the fat burning heart rate work?

So if you stay a certain heart rate you will mainly use fat as a fuel. It’s tempting to conclude that you have to exercise at this intensity to achieve the most weight loss. However before you get yourself a heart rate monitor you need to know if this is actually something you should focus on.

Fat is not the only energy source

Some people are not completely aware of this but fat isn’t the only source of energy (calories) the human body uses. This is how “low fat” foods became popular for weight loss and also the reason why they are not necessarily very helpful for that.

Your body mainly uses two kinds of energy: fuel from fat and fuel from carbohydrates.

When you eat carbohydrates your body turns those carbohydrates into glucose. But too much glucose in your blood is dangerous. It would cause things like organ failure.

Luckily your body has a smart system to turn this glucose into something else which isn’t as dangerous in higher quantities. This substance is called glycogen.

Glycogen matters

Glycogen can get stored in your liver and muscles. However there is only a limited amount of room to store glycogen.

Your body also has a solution for this, the human body is pretty smart. It can turn this excess glycogen into body fat with a process called lipogenesis. Your body basically tries to make sure no energy goes to waste.

Don’t worry if this sounds a bit complicated. The most important thing you have to know is that energy from carbohydrates gets stored in your muscles and liver and that too much glucose and thus glycogen ultimately gets stored as body fat.

When exercising less intensively you use fat as an energy source. At a certain high intensity of activity your body starts converting glycogen into glucose and using that as the main fuel.

So while the fat burning heart rate might burn the most fat it might not be the best heart rate for weight loss.

The optimal heart rate to lose weight

If you are like most people you consume at least some carbohydrates and protein. Even if you’re on something like the ketogenic diet. Excess protein and carbohydrates can get stored as glycogen. If you eat too much of these glycogen will be stored as body fat which is gaining weight.

This means that if you’re trying to lose weight your goal isn’t just to burn as much fat as possible. The real goal is to burn as many calories as possible both from fat and from glucose. Burning both will be helpful for losing or maintaining weight in the end.

When talking about cardio and HIIT the general rule is the higher the intensity (and heart beat) of the workout, the more calories you burn per minute. Most people are short on time. In that case a higher intensity workout will provide more weight loss results. On the other hand you probably won’t be able to sprint for 2 hours at a time.

There is also of course a limit to how high you can go. When you’re first starting out it’s also probably not a good idea to go for high intensity workouts right from the beginning.

When to keep an eye on your heart rate when exercising

Your heart is a muscle. It’s a bit harder to injure than most other muscles but that’s still possible and the effects are much worse.

If it’s been a while since you exercised and you gained some weight you probably don’t want to head into high intensity exercise right away. You slowly want to make your heart stronger again. This usually involves starting out with a lower intensity exercise at 50% of your maximum heart rate like for example walking.

In this case you can get a heart rate monitor to make sure you’re not overdoing it with intensity of exercise.

Another reason you might want to keep an eye on your heart rate when exercising is to make sure you’re pushing yourself enough. When you first do for example a 5 km run at 5 mph your heart rate might be something around 60% of your maximum heart rate.

If you keep doing this workout and you lose some weight sooner or later this percentage will go down. To make sure you keep yourself moving towards your weight loss goals you can aim to keep your workouts intense enough. You can also do this subjectively but it can be great to know for sure what your heart rate is.

A tool to measure your heart rate is no requirement for losing weight but it can offer some benefits.

Tools to measure your heart rate

There are multiple ways you can measure your heart rate. The options range from just the old way of tracking to fancier devices.

Any clock that counts seconds

The most inexpensive way you can measure your heart rate is with any clock that counts seconds. You just put your fingers on your wrist and count how many times your heart beats for 60 seconds. This is your current heart rate.

This method is a bit harder to do while working out.

Wrist monitor

There are a lot of fitness that measure heart rate. Often these devices track throughout the whole day. It’s also often possible to get a visually attractive graph of this data through apps.

This way of measuring your heart rate is a lot more convenient. Keeping on your watch on is the only thing you have to do. They usually also offer other interesting stats like distance travelled

Check out fitness trackers on amazon.

 Chest strap monitor

The last option you have for measuring your heart rate is a chest strap monitor. These straps are made of stretchable materials with a device in the middle. This device can then send the data to a smart watch or an app.

Check out chest strap monitors on amazon.

Which one is the best?

All these ways measure your heart rate accurately so it comes down to personal preference, budget and other features you may want in such a device.

Is the fat burning heart rate a myth or reality?

The fat burning heart rate can indeed help you burn more fat but that’s not the most important thing when you’re trying to lose weight. You want to use as much energy (calories) as possible, no matter what fuel it comes from.

This means that workouts with a higher heart rate, which means higher intensity, will help you burn more calories per minute than lower intensity workouts. Even if they are in the fat burning zone.

If you have a lot of time to workout you can choose a lower intensity so you can keep exercising for longer. If you’re just starting out it might also be smarter to start at lower intensities so your body as time to adapt to the new intense movements.