Buzz
Cardio machines are misleading you. Chances are you've encountered an elliptical workout claiming to keep you in the 'fat burning zone,' or seen a treadmill display suggesting your heart rate should hit a specific number to be in that zone. Don't buy into it. The fat burning zone is simply a myth.
These machines may claim the fat burning zone lies between 50 to 75 percent of your maximum heart rate (which they’re likely calculating incorrectly). But exercising within this range doesn’t magically burn more fat than any other type of exercise.
Fat loss isn't tied to your heart rate during exercise.
To lose weight, the key factor is how many calories you're consuming. It needs to be fewer than the total calories you burn throughout the day.
Can you burn more calories by working out? Absolutely. The longer and harder you exercise, the more calories you'll burn. How you structure your workouts is up to you. A one-hour walk burns roughly the same amount of calories as a half-hour run.
Your body is constantly burning fat.
Your body doesn’t store fat for some future need. It's always burning fat, even right now as you’re reading this while not moving at all, like while sitting on the toilet.
Fat burning is a slow, steady source of energy. But when you need to move fast and hard (like if a tiger suddenly appears in the bathroom), your body taps into other energy sources, including the sugar stored in your muscles for such emergencies. Fat still burns in the background, but it's not your body's primary fuel for this brief burst of energy.
When you're on a cardio machine at the gym, your body burns a combination of fuels. While fat burning might have increased a bit, a large portion of your energy comes from burning other fuels, including glycogen, the sugar stored in your muscles. (I’m simplifying it a lot; here’s a more detailed version if you're interested in the science.)
In the end, we’re always burning fat, though at times we also burn other types of fuel.
So, why is it called the fat burning zone?
This so-called zone is supposed to exist at a level that feels somewhat easy—a brisk walk, a light jog, or a comfortable pace on the elliptical or bike that you think you could maintain forever. If you're new to working out, it’s meant to make you feel reassured. You can exercise at a relaxed pace and still burn calories.
Here’s the nugget of truth: the harder you work out, the more your body calls on other fuels like glycogen. So, percentage-wise, you're burning a higher proportion of fat in this so-called 'fat burning zone.' But that's only because you're burning fewer calories overall.
The real fat burning zone, where we burn the highest percentage of calories from fat, is when we’re doing absolutely nothing. Like when we’re lounging on the couch or sleeping.
Which exercise zone is most suitable for you?
The answer depends on finding the right mix of enjoyment and effort that aligns with your personal goals and preferences. Consider the 'fat burning' zone as your entry-level, easier exercise zone, with progressively harder zones above it.
Opt for the 'fat burning zone' if you:
Prefer a gentler workout
Are new to exercise and find intense workouts daunting
Are pacing yourself for an extended workout session
Choose a higher intensity zone if you:
You're ready to push yourself
You aim to finish your workout quickly
You want to maximize calorie burn in a shorter time
To enhance your overall fitness, it's important to engage in all intensity levels: a mix of light cardio, moderate exercise, and intervals that push you to your highest effort. There's no one-size-fits-all approach to exercise.
