Cardio Vs. Fat Burn: What’s The Difference?

Often the terms “cardio” and “fat burning exercise” are used interchangeably. This is not really accurate. Cardio and fat burning exercise are a little different but seem confusingly similar to many people. So what’s the difference between them? How is exercise categorized as “Cardio” different from “Fat Burn?”

What’s known as “cardio” is an important type of exercise that is for training and strengthening your cardiovascular system, namely your heart and lungs. Fat burning exercise is often the same types of exercise as cardio but performed at a different intensity so as to maximize the use of fat for fuel. The key difference is the intensity level measured by the heart rate (HR) that you maintain through the workout. Maintaining a HR of between 60-70% of your Maximum Heart Rate (MHR) is considered the sweet spot for fat burning, and 70-85% of your MHR is designated for cardiovascular training.

Does this mean that working out harder won’t help burn fat? Overall, or just during the workout? How do you measure your heart rate? There’s a lot of information to unpack here, so let’s explain a few things.

What’s The Difference Between Cardio And Fat Burn HR Ranges?

Often described as “zones” there is a heart rate described as a percentage of your maximum heart rate, which corresponds with age, (more about this shortly). There is a target heart rate range for each of these types of training.

The heart rate range you want to hit for cardio is 75-85% of your max heart rate. This is a pretty high level of intensity, uncomfortably so for many people. Certainly this level of output is hard enough to limit the length of your workout to 30-45 mins. 85% feels very difficult to maintain for the average person. If you are 40 years old, this will be about 126 bpm (beats per minute) or more. I’ll explain more about this in a moment. As a rough example of this would be for an average 30-35 year old to run at about 7-8 mph.

The heart range usually ascribed to as the fat loss zone, will be 60-70% of your max heart rate. Most people do this at the lower end of this scale, as the difficulty quickly increases as your heart rate rises. As another rough example: for an average 30-35 year old, an exercise that would put you in this range would probably be walking up a slight incline (lowest setting on a typical treadmill) at about 3.5 miles per hour.

Both of those examples were just intended to give you an idea of the level of intensity required to train in these ranges, and are far from exact. Obviously, levels of conditioning, weight, and other fitness and health factors each play a role in the differing capabilities of individuals.

What Is The Best Heart Rate To Burn Fat?

From anywhere from resting up to about 70% of your maximum heart rate your body will be getting most of its energy from its primary source – your stored body fat. At exertion levels below this, about 60% of the calories expended are fat calories.

Sugar is quick, easy energy. So when the demand for energy from exercise is not very high, the body tends to save this easy energy for when it might need it later. Burning fat for fuel instead.

So you are burning a higher percentage of fat but not necessarily more, or even as much in absolute terms, as when you work out a little harder, in the cardio range.

What Is the Best Heart Rate For Cardio?

To thoroughly work and strengthen the cardiovascular system you should train harder. You need to workout at a level of intensity where you maintain a heart rate of 75% or more of your maximum heart rate. 75-85% is usually accepted as the correct heart rate for this type of training.

Realistically, going any higher would not be practical for many people. Even training at 85% of your MHR can be a pretty unpleasant experience if you are not prepared for it.

Maximum Heart Rate (MHR) Explained:

Your maximum heart rate is the fastest your heart can theoretically beat. This is calculated using a very simple formula:

220 – Your Age (In Years) = Your Maximum Heart Rate (MHR)

So for example, a 40 year old will have a MHR of 180 bpm (beats per minute).

This person will want to exercise with their heart rate between 108-126 bpm to be in the fat-burning zone/range of 60-70%..

In order to be doing true cardiovascular training, that same person’s heart rate needs to be a little higher, between 126-153 bpm. This is the cardio zone/range of 75-86%.

Here’s A Helpful Chart:

Here’s the heart rate ranges associated with both types of exercise. Age shown in years, HR shown in beats per minute:

Age	Max HR	Fat Burning Zone HR (60-70%)	Cardio Zone HR (75-85%)
20	200	120-140	150-170
25	195	117-136	146-165
30	190	114-133	142-161
35	185	111-129	138-157
40	180	108-126	135-153
45	175	105-122	131-148
50	170	102-119	127-144
55	165	99-115	123-140

How Do I Measure Heart Rate?

If you have a watch, or clock with a “second” hand, you can easily calculate your heart rate.

You simply count your heart beats for 6 seconds, then multiply it by 10. So if you count 12 beats in 6 seconds, your approximate heart rate is 120 bpm.

Most gym cardio equipment, such as treadmills and elliptical machines, will have built-in heart rate monitors. Usually there are shiny metal electrodes on the handles that you grasp so the machine can read your heart rate.

Of course there are also Fitbits and other useful devices that you can buy to make this an even simpler process, or compile data throughout your workout, or the whole day. But if you like to keep things simple, a simple watch will do, using the method above.

Is That Really The Only Difference?

Think of a form of aerobic exercise, like swimming or running. Imagine a pace that you can maintain for a one hour workout, but could then easily keep going for several more hours. This is the fat burning level of intensity, wherein more of the calories burned come from fat.

Now imagine doing that same activity at a pace where you can do 30-45 mins but at the end you are worn out and couldn’t go another 5 mins at that speed. This is the level of intensity that will actually condition and train your cardiovascular system. In this zone, your body primarily relies on carbohydrate for fuel, but will burn more calories per minute that the less intense fat burning zone.

So the difference is not just mathematical, you will definitely feel the difference. Training within the cardio zone is much harder than the fat burning zone. But also more rewarding.

Won’t Going Harder Burn More Calories?

Yes it most definitely will burn more calories. Not only will the harder cardio style exercise burn more calories per minute or hour, but it will also cause your body to keep burning calories at a higher rate, for longer after your workout.

This is known as EPOC (Excess Post-exercise Oxygen Consumption). It’s basically your body hustling to recuperate and refuel your cells. The more strenuous the exercise, the more recovery is needed.

Won’t Going Harder Burn More Fat Too?

Ultimately, yes, you will burn more fat if you train harder in the cardio zone. Just not as a percentage of the calories that you burn during the actual workout.

So working out for an equal amount of time, at a lower heart rate of 60-70% MHR, will burn more fat calories as a proportion of total calories burned. But, working out at a higher heart rate of 75-85% MHR, will burn more calories overall and after the workout.

The fact that a lower percentage of the calories used during your workout comes from fat doesn’t really matter, because your blood sugar is basically future fat.

Which Should I Be Doing?

What is your goal? General health, weight loss, to play a sport?

Either approach is respectable, but you’ll be doing your health, and longevity, a service if you are willing to push yourself a little harder and do your training with your heart rate in the cardio zone, or as close as you can get.

The higher intensity cardio zone also means that it is going to be more effective overall for fat loss or just to maintain your athletic ability.

You will get more in return for your effort with cardio zone training, but it’s harder work and may be less likely to actually get done for some of the less motivated of us!

The workout that you’re actually going to do is always the best one, so do what you want to do. Just don’t let yourself off easy.

If you’re willing to put in the hard work to get into and stay in the 75-85% MHR zone, you will get the benefits of:

Stronger heart and lungs
More calories burned total
Shorter workouts for the same, or better, results

Enhanced skill at your chosen form of exercise.

Which Zone Is Best For Me: Cardio Or Fat Burn?

In the end, the fat burning zone wins for most people because its easier, and still effective. It also comes with the timeless excuse that you burn more fat at lower intensity levels!

It comes down to personal preference. Are you the type of person who’d rather bang out your workout in as little time as possible and get the most out of your training? Or would you prefer to go for a leisurely bike ride or walk for 1-2 hours and be happy that you are active? Both types of exercise will help you lose fat and stay in better health than a sedentary person.

If you are a results-oriented person, you owe it to yourself to go a little harder, make each workout count a bit more, and get your heart rate up above 75% of your MHR.

How Long Should I Train In The Fat Burn Zone/Range?

If you want to lose fat, or just keep your workouts a little easier, doing your exercise in the fat burning zone may be your choice. It is possible to continue training in this zone is possible for much longer, so 1-1.5 hour workouts are preferable, 5 days a week. If you are exercising with a heart rate on the lower end of around 60% max, this won’t be too hard.

How Long Should I Train In The Cardio Zone/Range?

If you decide that you want the maximum bang for your buck and are looking forward to reaping the benefits of a more intense, cardio zone workout regimen, you can simply do 30-45 minutes per session. 5 workouts a week is best, preferably with the 2 rest days being nonconsecutive. This will be plenty to burn off fat and get your heart and lungs in tip-top shape.