There has always been a bit of controversy surrounding the difference between fat-burning and cardio zones amongst health and fitness professionals.  This is mainly due to neither of them being a scientific term and the reality is that different health and fitness gurus use the term differently.

Some fitness experts refer to aerobic exercise as fat-burning or cardio exercise. The other half calls moderately intense exercise (below your aerobic threshold) fat-burning mainly because it burns a higher percentage of fat calories than glycogen calories.

Let’s try and take a bit of the confusion away.


If you consider the fat-burning and cardio zones two completely different workout targets, then fat-burning is the baby of the two.

It takes place at roughly 50 percent to 60 percent of your maximum heart rate (or effort). At this heart rate, most of the calories you burn come from stored fat. With aerobic, or cardio exercise, you burn fat and glycogen at a roughly 50:50 ratio, while during anaerobic exercise (HIIT High intensity interval training) such as tennis or sprint intervals, you burn most of your calories from glycogen.  Glycogen is carbohydrates now in your system and ready to be used as fuel.

In the fat-burning zone, you’ll burn fewer total calories than you do with aerobic exercise. If your goal is to burn the most calories and most total fat calories, then an aerobic, or cardio, workout, is a better choice for you. If your goal is to burn calories while you build stamina and endurance to create more intense workouts later, then fat-burning (longer duration less effort) will be the exercise for you is for you.


Some people refer to any kind of exercise that raise your heart rate during your workout as cardio. Even a brisk walk, or using a treadmill at level 3 to 5 (out of 12). If on the other hand, you understand cardio to be activity performed in your aerobic heart rate range, you’ll work at a pace similar to jogging, reaching 70 percent to 80 percent of your maximum heart rate (or effort 7 from a scale of 1 – 10).

Experts take what you call the the “talk test” during your workouts to determine in what range you are.  If you are sweating and breathing hard, but can still talk, you haven’t reached your aerobic threshold.


The bottom line is; the harder you work, the more calories you will burn, which is why even though you burn more calories from fat during fat-burning workouts, you will obviously burn more total fat calories with more intense exercise. For example, walking on a treadmill/outdoors a medium pace, in the “fat-burning zone” it will help a 80kg person burn roughly 200 calories per hour. Raising that to a steady jog, the same person will burn approximately 600 calories per hour. The American Heart Association recommends that you perform moderate-intensity workouts for 150 minutes each week, or 75 minutes of vigorously intense each week.  That translates to the simple fact that it doesn’t really matter if you train in the cardio or fat burning zone as long as you get it done.  The only difference is the time you spend burning the same amount of calories.

Hot to Determine Your Ideal Heart Rate

To find your ideal heart rate for exercise, start by determining your maximum heart rate. The method we commonly use to determine this, is to subtract your age from 220. Some Medicine researchers recommend that women subtract 88 percent of their age from 206 to find a more accurate maximum heart rate. Once you know your maximum heart rate, multiply it by .50 and .60 to get your fat-burning target heart rate range. To find your aerobic, or cardio, heart rate zone, multiply your maximum heart rate by .70 and .80. If you have a good heart rate monitor this can also help you stay in your ideal zone.

In conclusion I would recommend personally a mixture of the two.  HIIT is in my opinion one of the best type of exercises for fat burning.  I also always recommend doing a bit of both so that you don’t get too bored with your training.  Hope this was helpful.