At lower intensities of exercise, muscles burn a higher percentage of fat than carbohydrate, but not necessarily more total fat, or more total calories, than at higher intensities. This is a subtle distinction, but it's an important one.

Is low intensity exercise better for weight loss?

Also, while high-intensity exercise is more effective for fat loss than low-intensity exercise on a minute-per-minute basis, low-intensity exercise has the greater overall capacity to produce weight loss because it's possible to do so much more of it.

Why does low intensity cardio burn fat?

"In terms of effective fat burning, the body needs oxygen," she explains. "Training at a lower intensity actually means that more oxygen is available to be used by the body to break down fat and use it as energy."