I think we have all heard at one point or another that doing low intensity cardiovascular exercise will burn more fat than if we do a high intensity exercise. The explanation behind this is that fat needs more oxygen to burn. So if we are doing a high intensity activity or anaerobic activity, we will be using only carbohydrates because there is not enough oxygen to burn the fats. Well, this is false. Let me explain.
It´s true that you burn more fat at a lower intensity, but only as a PERCENTAGE of the total calories burned. This doesn´t mean that as exercise intensity increases, fat burned decreases. It simply means, that as intensity increases you just burn more of both (carbohydrates and fats), with carbohydrates making up the largest percentage of calories. So let´s put an example to clarify:
Low intensity exercise (walking) done during 45 minutes – imagine you burn 300 calories, of those 300 calories 60 percent are calories from fat. So of those 300 calories 180 were fat calories.
High intensity exercise (sprints) done during 30 minutes – let´s say you burn 800 calories, of those 800 calories 30 percent are calories from fat. So of those 800 calories 240 were from fat calories.
* Plus, it has been proved that, the higher the intensity is during your cardio, the more calories you will continue to burn after the exercise. This is also another reason why high intensity interval training is so effective and popular.
So in conclusion, low intenstity activity burns only a higher PERCENTAGE of fat calories, that doesn´t mean it burns more fat calories.
In my next blog I will talk about running, to see if it really is that efective in people who run to lose weight or get in shape. Hasta la proxima.