What’s ‘The Afterburn’

You’ve probably heard of  The Afterburn

Excess Post-exercise Oxygen Consumption – EPOC

Lets have alook at this EPOC thing then……

Excess post-exercise oxygen consumption, or EPOC, or as you have probably heard it called, the ‘afterburn’ is an increased rate of oxygen intake following anaerobic and aerobic exercise.  This process is intended to reduce the body’s “oxygen debt.”

During recovery, oxygen (EPOC) is used in the processes that restores the body to a resting state and put it back to the state it was in before exercise. This process also includes restoring hormone balance, replenishing fuel stores and repairing muscle cells, Post-exercise oxygen consumption also replenishes the phosphagen system. New ATP (Adenosine triphosphate) is synthesized and some of this ATP donates phosphate groups to creatine until ATP and creatine levels are back to resting state levels again.

Post-exercise oxygen is also used to oxidize lactic acid. Lactic acid is produced during exercise and then travels along with the blood to the kidneys, heart, and liver. An increased amount of oxygen is necessary to convert the lactic acid back to pyruvic acid at these organs

Another use of EPOC is to fuel the body’s elevated metabolic rate from the rise in body temperature which has occurred during exercise.

So as you can see so far there are many thing happening during this process which require oxygen to take place. In response to exercise, fat stores are broken down and free fatty acids (FFA) are released into the blood. During recovery, the direct oxidation of free fatty acids as fuel and the energy consuming re-conversion of FFAs back into fat stores both take place.

So why is it referred to as ‘the afterburn’ ???

The EPOC effect is at its maximum soon after the exercise is completed and decreases to a lower level over time. One experiment found EPOC increasing metabolic rate to an excess level that decreases to 13% three hours after exercise, and 4% after 16 hours. Another study, specifically designed to test whether the effect existed for more than 16 hours, conducted tests for 48 hours after the conclusion of the exercise and found measurable effects existed up to the 38 hour post-exercise measurement. So you can see from this that high intensity interval training will have your body using and burning more calories for longer once exercise has stopped.