Is There Really a Fat-Burning Zone?

Burning fat. If ever there was a subject in the world of fitness that grabs everyone’s attention it’s that.

What’s the best way to do it? What exercises are best for it? Can you burn calories while resting?

In this article, we’re going to look at fat burning and delve into the science behind training zones and fat metabolism.

Stay with us while we shed a little light – and maybe a few pounds – on this hottest of topics.

OK. Let’s start by looking at training zones.

If the ‘fat burning zone’ really does exist, where on earth can we find this holy grail?

Heart rate training zones are percentage ranges of your maximum heart rate (MHR). Each zone represents a different level of exercise intensity.

So first, we need to establish your MHR, and there are several ways you can do it.

Let’s look at two very straightforward methods.

The most simple calculation is the Fox formula: 220 – your age = your MHR. So, for example, if you’re 30 years old, your MHR would be 190 beats per minute.

Another method is the Tanaka formula.

This states that 208 – (0.7 × your age) = your MHR. So, if you’re 30 years old, your MHR would be 187 beats per minute.

As there’s not a great deal of difference, it doesn’t really matter which formula you use.

But once you’ve worked out your MHR, you can make more sense of the training zones.

The table below gives you an idea of each zone.

There is certainly debate about the actual percentage of MHR where fat burning occurs. But it’s widely accepted that this percentage is somewhere between 60% and 80%.

Thus, we can deduce that exercising with a heart rate around 65-70% of your MHR (continuously for between 20–40 minutes) will help burn fat effectively.

Moreover, getting to grips with all the zones means you can tailor your workouts to your goal. Whether it’s fat loss, endurance, or improving your performance.

When you enter the ‘fat-burning zone’ your body body will predominantly use fat as its primary energy source. At this crucial point, two things happen:

1. Your body has sufficient oxygen to metabolise fat for energy.
2. A higher percentage of calories burned come from fat compared to carbohydrates.

They don’t call it the fat burning zone for nothing, right?

Well, while it’s true that a higher percentage of fat is burned at lower intensities, we have to consider the total number of calories expended:

Low-intensity exercise: Burns a higher percentage of fat but fewer total calories.

High-intensity exercise: Burns more total calories, including fat and carbohydrates.

Therefore, high-intensity workouts can lead to greater overall fat loss due to increased calorie expenditure.

So, it’s probably best to mix things up.

After all, your heart is a muscle that needs to be trained in order to keep it in good condition. The odd high intensity workout can certainly help do that.

And, there’s something else you need to consider…

You’ll recall at the start of this discussion we mentioned burning calories while resting.

If being in the fat burning zone is the proverbial cake, then burning calories while resting would surely be the icing. Or rather the berries to your overnight oats—let’s keep it healthy, shall we?!

Ever heard of EPOC?

Let us explain.

High-intensity exercises, such as High-Intensity Interval Training (HIIT), can elevate your metabolism even when you’ve finished exercising.

This phenomenon is known as Excess Post-exercise Oxygen Consumption (EPOC). And it can lead to additional calorie burn. As you would expect, this effect is less pronounced in lower-intensity workouts.

EPOC is another reason why it’s a good idea to add variation to your workouts.

OK. Let’s compare two forms of exercise and their relative intensity. Brisk walking and sprinting.

Going for a brisk walk may not seem that great compared to donning your running spikes and hitting the track.

But the key here is your ability to maintain the intensity long enough for the exercise to have an effect. There’s little point hitting 90% MHR with a sprint if that 30-second dash is all you can muster.

A 20-30-minute brisk walk at 65-70% MHR, on the other hand, is much more attainable. And it falls nicely into the fat-burning zone. The operative word here is brisk. Meandering at a leisurely pace and pausing to take in the scenery won’t cut it.

That’s not to say you shouldn’t sprint. Indeed, sprinting reaches higher zones and burns more calories in less time. But it requires greater effort and longer recovery.

OK. What if there was a form of exercise that targets the best of both worlds?

Well, folks, there is. Our old friend HIIT.

During a HIIT session, you might, for example, sprint for 30 seconds and then walk briskly for a minute.

Prefer indoor cycling? You might translate this as standing and pedalling fast for 30 seconds then sitting and pedalling at a slower rate for one minute.

Incorporating both intensities into your workout can have enormous benefits.

Least of all, a good old dose of EPOC.

The fat burning zone is a valid concept, but it’s not the sole factor in effective fat loss. Total calorie expenditure, exercise variety, and your individual preferences play crucial roles.

And let’s not forget diet. That will need to be squeaky clean in order to enhance your efforts in the gym.

Perhaps the best solution is to combine different training intensities. That way you can unlock numerous health benefits and support sustainable fat loss.

Need help?

At Kidsgrove Sports Centre, our Personal Trainers are here to guide you. Their expertise in diet and training can help you reach your goals.