A lot of people that are beginning an aerobics routine wonder about their target fat burning heart rate. However, they fail to consider that you don’t actually burn the most fat in the so-called fat burning zone. So, how did this myth perpetuate itself? Simple, there is some truth in the statement but it’s been skewed by people who want to make exercise easier.
Fat Burning Heart Rate Calculation
Before I debunk the fat burning zone myth, I would like to discuss target heart rate calculations. First you have to calculate your max heart rate. The simplest way is to subtract your age from 220. So if you’re 30 years old, your max heart rate is around 190 beats per minute. Generally, the fat burning zone is thought to be between 60-65% of your max heart rate. Therefore, the fat burning heart rate zone for a 30 year old would be between 114 and 124bpm.
Fat Burning Zone Myth
When you exercise in the fat burning zone, you do actually burn the highest PERCENTAGE of calories from fat. The problem is that higher intensity exercise burns more calories and more fat calories due to a significant after-burn effect whereby your body continues burning fat after you complete your aerobics routine. Sadly, the bottom line is that there’s no shortcut when it comes to burning fat.
If you’re a numbers person, the chart below shows how many calories a 130lb woman burns during cardio based on a study from The 24/5 Complete Personal Training Manual:
As you can see, the percentage of fat calories burned is higher but total fat calories burned is actually lower.
A Better Aerobics Routine
So, how can you burn more calories?
Workout as hard as you can!? That’s it? Yes, in fact that is it. An intense workout is what it takes to burn more calories and ultimately lose more fat. Does the fat burning zone have a place in such a routine? I’d argue that it does. Low intensity cardio done in the fat burning zone allows your body time to recover. You can’t possibly perform a high intensity workout every day, but you can do some low intensity cardio like walking every day or intersperse periods of fat burning cardio within interval training.
As I’ve discussed previously, my favorite cardio routine involves high intensity interval training (HIIT). After a warm-up, I perform 10 minutes of short interval HIIT (15 second sprint, 45 second jog), 10-25 minutes of steady state fat burning cardio (light jogging), and 10 minutes of long interval HIIT (1 minute fast run, 1 minute jog). Done 3 times per week, this is all the intense cardio I need. I walk on alternate days when possible.
Don’t Try to Take the Easy Road
The fat burning zone myth would have you believe that you can burn more fat by working out less intensely. The truth is that “there is no free lunch.” You can’t expect to burn more calories by working out less intensely. While your fat burning heart rate provides a good range in which to perform low intensity, steady state cardio, a successful aerobics routine is going to have to include some high intensity cardio that gets you close to your max heart rate. That’s when the real fat burning zone kicks in!
