Cardio machine manufacturers generally have workout programs you can do in two modes: “fat burn” and "cardio.” If you’re like most people who use these machines, you’ve probably wondered what that meant. Which mode should you choose? If want to burn off fat, you should go with fat-burning mode, right?
For years people have been asking that same question, and over time the answer has gotten more and more complicated. We know a lot more nowadays about how working out works. So here’s a simple explanation to clear up the confusion—which has gone on for far too long.
Let’s start with what the human body uses for energy. Carbohydrates and sugars, in chocolate milk for example, are our main source. We also use lipids, better known as fats, and you may be surprised to hear that proteins are an energy source too. Our body constantly uses all three fuels, but it keeps altering the mix.
So, the only difference between fat-burning mode and cardio mode is the intensity of the workout. Fat burn mode aims to get our heart rate up to 65% of its maximum, while cardio mode lets us go up to 85%.
So, given that we work less hard in fat-burn mode, why do they call it that? Simple: At rest, we burn more fat than we do sugars. The machine uses the same principle, which is why fat-burn mode keeps our heart rate lower.
Picture two workouts, each of which burns about 500 calories but uses a different mix of sources along the way:
That means we burn more fat, 11 more grams per 500 calories, by walking for 55 minutes than by running for 42. That’s how it works.
At that rate you’d need 90 walking sessions, or 7-and-a-half months at 3 workouts a week, to lose 10 kg of fat. Crazy? You bet.
So what’s the mode for you?
If you ask us, neither. Go with manual and create your own program with stretches of high intensity and low intensity.
To burn fat, it’s better to burn more energy each day and reduce your caloric intake—it's faster and more effective than picking a mode on a treadmill.
Once again, the tried-and-true formula triumphs over marketing fads.