“I’m going to do my cardio.” What does that mean? As with the way you eat and any other part of your workout, there should be a purpose to your cardio. It’s a huge mistake to think that all cardio is the same.
By far the biggest reason most people do cardiovascular type workouts is to burn calories. I won’t get into the fact that using cardio to burn calories in order to lose or maintain your weight is seldom the best strategy, the fact is, people are going to keep going down that path, so at least let’s do it most effectively.
First, let’s dispense with the myth of the “Fat Burning Zone:” that hypothetical range of heart rate that supposedly burns the most fat.
There are a number of problems with this theory: First, that heart rate zone is WILDLY unpredictable for any given individual.
The error in the heart rate charts is greater than the size of the charts themselves. You may think you’re in the “zone” but be completely outside of it.
The next issue is that it really does not matter whether you’re burning fat during the workout or not, just that you’re expending calories.
Yes, if you go slow enough that you are using only fat for fuel, you’ll be able to go longer, but if you go faster, and deplete your glycogen stores (carbs) or even faster and go anaerobic through intervals, you’ll end up burning more calories and fat over the course of the post exercise period.
That’s what really counts.