5 Things to Know About Excess Post-Exercise Oxygen Consumption (EPOC)

What happens to your engine at the end of a long car trip? It does not require a degree in automotive engineering to know that once you have reached your destination, your carʼs engine stays warm as it gradually cools to a resting temperature. 

Here’s a cool fact: The same thing happens to your body after exercise. Similar to how a carʼs engine remains warm after being turned off, once a workout is over and youʼre back in your daily routine, your bodyʼs metabolism can continue to burn more calories then when at complete rest. This physiological effect is called excess post-exercise oxygen consumption, or EPOC. Also known as oxygen debt, EPOC is the amount of oxygen required to restore your body to its normal, resting level of metabolic function (called homeostasis). It also explains how your body can continue to burn calories long after you have finished your workout. 

Your metabolism is how your body converts the nutrients you consume to adenosine triphosphate (ATP), the fuel your body uses for muscular activity. ATP is produced either with oxygen using the aerobic pathways or without oxygen using the anaerobic pathways. Exercise that places a greater demand on the anaerobic energy pathways during the workout can increase the need for oxygen after the workout, thereby enhancing the EPOC effect. 

Here are five things you should know about EPOC and how it can help you achieve optimal levels of calorie burning from your workouts.

Exercise that consumes more oxygen burns more calories. 

The body expends approximately 5 calories of energy to consume 1 litre of oxygen. Therefore, increasing the amount of oxygen consumed both during and after a workout, can increase the amount of net calories burned.

Circuit training and heavy resistance training require ATP from the anaerobic pathways, leading to a significant EPOC effect

Strength training with compound, multi-joint weightlifting exercises or doing a weightlifting circuit that alternates between upper- and lower- body movements places a greater demand on the involved muscles for ATP from the anaerobic pathways. Increased need for anaerobic ATP also creates a greater demand on the aerobic system to replenish that ATP during the rest intervals and the post-exercise recovery process. Heavy training loads or shorter recovery intervals increase the demand on the anaerobic energy pathways during exercise, which yields a greater EPOC effect during the post-exercise recovery period.

High-intensity interval training (HIIT) is the most effective way to stimulate the EPOC effect

The body is most efficient at producing ATP through aerobic metabolism; however, at higher intensities when energy is needed immediately, the anaerobic pathways can provide the necessary ATP much more quickly. This is why we can only sustain high-intensity activity for a brief period of time—we simply run out of energy. HIIT works because during high- intensity exercise ATP is produced by the anaerobic pathways; once that ATP exhausted, it is necessary to allow ATP to be replenished. The rest interval or active-recovery period during an anaerobic workout allows aerobic metabolism to produce and replace ATP in the involved muscles. The oxygen deficit is the difference between the volume of oxygen  consumed during exercise and the amount that would be consumed if energy demands were met through only the aerobic energy pathway.

EPOC is influenced by the intensity, not the duration of exercise. 

Higher intensities require ATP from anaerobic pathways. If the ATP required to exercise at a particular intensity was not obtained aerobically, it must come from the anaerobic pathways. During EPOC, the body uses oxygen to restore muscle glycogen and rebuild muscle proteins damaged during exercise. Even after a HIIT workout is over, the body will continue to use the aerobic energy pathway to replace the ATP consumed during the workout, thus enhancing the EPOC effect. 

Resistance training can provide a greater EPOC effect than running at a steady speed. 

It was found that when aerobic cycling (40 minutes at 80 percent Max HR), circuit weight training (4 sets/8 exercises/15 reps at 50 % 1RM) and heavy resistance exercise (3 sets/8 exercises at 80-90 % 1RM to exhaustion) were compared, heavy resistance exercise produced the biggest EPOC. 

Eternally Fit – ICE & FIRE

This is why our ICE and FIRE programs are so effective. But there is a very big proviso; YOU must make it work by ensuring your intensity levels are between 8 and 10 (1 being sitting watching TV, and 10 being running for your life!)

If you want the effect of the EPOC (burn more calories while NOT exercising) then you must put the work in to create it!