Quick Thoughts on the Afterburn Effect

     The afterburn effect simply means that your body will continue to burn fuel after your workout is over in order to return itself to a resting state and adapt to the stresses that are being put on it.  As you exercise, your body depletes energy stores and incurs small amounts of damage to the muscles and connective tissue. After the exercise is over your body must repair the damage that was done, replenish energy stores that were depleted, and adapt so that it can handle similar stress in the future.  All of these processes require the body to use more energy after a workout is over before it can return to a lower metabolic baseline.  The longer the transition to baseline, the more calories that will be burned as a result of a single workout.

     Afterburn is also known as EPOC (excess post-exercise oxygen consumption), and though it does dissipate relatively quickly over a couple of hours, the effect can be shown to linger in some small amounts for up to a couple days.  As the intensity and duration of a workout increases, so does the amount of stored energy that is depleted and the amount of tissue damage that is done.  So naturally the afterburn effect will last longer after high intensity workouts and workouts that last longer.

     When designing workouts, there is a balance to be had between intensity and duration.  The longer a  bout of exercise lasts, the less intense it is likely to be.  For example, think about the intensity difference between a sprint and a long distance run.  As duration goes up, intensity must at some point go down.

     A popular way to maximize the amount of intense exercise that can be done in a small amount of time is to separate bursts of intense exercise with small periods of rest.   This is known as "High Intensity Interval Training" or HIIT, and is an excellent way to take full advantage of the "afterburn effect".  One easy way to mix HIIT into a program is to finish a workout with a Tabata Interval, which is simply 8 rounds of 20 sec maximum intensity exercise followed by 10 sec of rest.