Aerobic v.s Anaerobic

The word “aerobic” refers to the aerobic energy system and is one of the three ways your body can fuel exercise. Whether conscious of it or not, you are constantly using your aerobic system whether your sleeping, doing chores or exercising. In this system, you’re using oxygen to burn a combination of fat and glycogen (the form of carbohydrate your body uses for energy) to fuel your body.

All-out exercise is anaerobic. Your body can not use oxygen to burn fuel so it uses chemicals inside your body to generate the energy it needs. In this system, your body uses glycogen rather than fat to keep you moving. Your body has two systems for this; one for very short bouts (up to 10 seconds) and the other for longer dashes (up to a minute).
Looking at both these systems, you’d think that exercising with the aerobic energy system would be better because you’re burning fat through it. However, the amount of fat you burn during exercise is less important than the amount you burn when you aren’t exercising. This is what’s referred to as the “after burn,” or calories your body continues to burn after your workout is over. Intensity if the most important factor in determining post-workout metabolism (after burn).

Therefore in order to be more efficient and burn a greater amount of calories, workout at higher intensities (using your anaerobic system). Rather than run for an hour on the treadmill; perform a 15 minute high intensity interval. Instead of spending an hour lifting weights, reduce your rest periods or move from exercise to exercise without rest.