The fat burning zone refers to the percentage of your maximum heart rate where most of the fuel being burned comes from fat. Once upon a time, it was believed that you should measure your heart rate while exercising to ensure you stayed within this range. However, this concept is not very useful.
It is true that at certain exercise intensities, you burn more fat than carbohydrates for fuel. BUT, when you exercise at a lower intensity, you are burning fewer total calories. The total calories burned are what matter most for weight loss.
For fat to be used as fuel, the presence of oxygen is required. At higher intensities, when you’re more out of breath, your bodily tissues receive less oxygen. Additionally, it’s easier for your body to break down stored carbohydrates (glycogen) for fuel. So, during exercise, your body initially relies on carbohydrates for fuel. At high intensities, however, your body depletes glycogen quickly, forcing it to utilize stored body fat for fuel. At this high intensity, you burn more calories compared to a lower intensity.
Certainly, burning more calories is beneficial for weight loss, but what’s most important is your adherence to exercise. If you’re pushing yourself to do high-intensity exercise that you don’t enjoy, you’re less likely to stick with it. If lower-intensity exercise is your preference, you can still lose weight doing this; you just need to do it for a longer duration. Additionally, don’t forget that exercise offers benefits beyond just weight loss—it keeps your cardiovascular system healthy!
Ultimately, the best exercise for you is the one that you enjoy and will, therefore, stick with in the long term.