By now I’m sure you’ve heard of the fat burning zone. This zone is the magical target heart rate range that you’re supposed to exercise in to burn more fat. Do I sound a little cynical? Let me explain to you the fat burning zone myth.
How to Calculate the Fat Burning Zone Heart Rate
To determine what your fat burning zone heart rate is supposed to be, use the following simple formula:
- Take 220 minus your current age = MHR (Age predicted max heart rate)
- Multiply your MHR by 0.6 to get the low end of your fat burning zone
- Multiply your MHR by 0.75 to get the high end of your fat burning zone
So take a 35 year old person for example. To find the MHR:
- 220 minus 35 (age) = 185
To find the low range of the fat burning zone:
- take 185 and multiply it by 0.6 — (185 * 0.6 = 111 beats per minute)
This is your target heart rate for the low end of the fat burning zone
To find the high range of the fat burning zone:
- take 185 and multiply it by 0.75 — (185 * 0.75 = 139 beats per minute)
This is your target heart rate for the high end of the fat burning zone.
Based on the theory of the fat burning zone, if you were to work out with a heart rate between 111 and 139 beats per minute, you would burn a higher percentage of fat during exercise than if you went above that number into the anaerobic zone.
Is the Fat Burning Zone Real?
Based on this theory and explanation, the fat burning zone is absolutely true! Bet you didn’t expect me to say that. Here’s the kicker though. Do you want to burn an even higher percentage of fat? Sounds good doesn’t it? Here’s the secret – all you have to do is watch some TV or go to bed. What? What people fail to understand is that you burn the highest percentage of fat calories while at rest.
Using carbohydrates for energy requires high-intensity exercise. The lower your heart rate is, the fewer amount of carbohydrates you will use. You have the lowest heart rate while you are resting. Therefore, you burn the highest percent of calories from fat while at rest.
You might have picked up on something by now. I never said you burn the most fat while at rest. I said you burn the highest percent of calories from fat while at rest. What’s the difference? Take a look at the following chart.
As you might have noticed from the table above, the total fat calories burned was lower when staying in the fat burning zone (120 fat calories burned vs 135 fat calories burned for high-intensity exercise).
The reason this is the case is because high-intensity exercise burns more total calories. This is what it all comes down to – total calories burned. Does it really make sense to you that if you don’t work as hard, you are going to get better results? I will never tell someone “slow down…you’re working too hard.”
Why the Fat Burning Zone is a Moot Point
All this talk about fat burning zones and target heart rates really doesn’t matter anyways. The average person only burns about 100 calories for every mile they run. Most people burn a few hundred calories during their workouts. And while this is great, it’s only a small percentage of the total calories you burn during the day.
You actually do burn the majority of your calories while at rest. Your body and your muscles need calories to build and maintain themselves. Your body needs calories to sustain life – a lot of them. This is why it’s so important to build muscle if you want to efficiently burn fat. The more muscle you have, the more fat calories you will burn during the day while at rest, and the better the metabolic environment will be for releasing fatty acids.
Focus on building muscle, and having a great diet. Then, if you want to lose weight, create a calorie deficit by either lowering your calories, or by adding in some extra physical activity, or a combination of both. Forget the fat burning zone, and instead focus on total calories burned. Work hard.