Understanding EPOC

Often referred to as “after-burn”, EPOC stands for excess post-exercise oxygen consumption. It is the actual amount of energy (calories) that the body continues to burn post-exercise.

I speak often about high intensity interval training (HIIT) on Catapult Fitness Blog. HIIT is done by alternating brief periods or high intensity work (85% or more) with a brief recovery period. HIIT is an example of an anaerobic exercise, which means that an inadequate amount of oxygen is being delivered to working muscles during the course of the exercise.

When inadequate oxygen is available lactic acid is produced. Lactic acid is what gives you that burning feeling during a workout. It leads to muscle fatigue and must be burned up by the body during a recovery period before another anaerobic bout of exercise can be attempted. This recovery period also allows the muscles to use oxygen to replenish the energy used during HIIT.

Conversely, aerobic or “steady-state” exercise uses oxygen at a constant rate with no accumulation of lactic acid.

While both anaerobic and aerobic exercise burn calories and create some EPOC effect, EPOC increases dramatically with intensity thus making anaerobic exercise a more effective means for fat loss.

A commentary in the December 9, 2005 of the Journal of the International Society of Sports Nutrition examined aerobic and anaerobic energy expenditure for two exercise tasks of equal work using a treadmill.

The results of the study showed that the steady-state exercise tends to burn more calories during the actual exercise than interval training, while interval training generates a higher EPOC leading to a much larger number of total calories burned.




Ultimately, HIIT results in significantly more calories burned in a much condensed period of exercise.

This is not to say that steady-state cardio does not have a place in your workout routine. Interval training should be limited to 2 – 3 times per week to lessen the risk of injury and allow for an adequate recovery period.

Steady-state cardio on the other hand can be performed daily, depending on duration and intensity level.

There are a myriad of HIIT exercises that can be found on the Web.

Hopefully you can use this information to maximize your workouts and turn your body into a fat burning machine!

Train hard; stay strong.

Peace.

Susan