But how can this possibly be? Everywhere you look, it’s always said that long-duration, low-intensity training is best for fat loss. All high-intensity work does is burn carbohydrates, right? Wrong. After reading this article, I guarantee you’ll develop a new respect for high-intensity cardio training for fat loss. Low-intensity exercise is defined as working at a heart rate of about 60% to 65% of your maximum heart rate (which is equal to 220 - your age = maximum heart rate, thus if you are.