I’m sure you’ve read the term in an article or heard a trainer say it at your gym, but what is EPOC?
By definition, EPOC (Excess Post-Exercise Oxygen Consumption) is the increased rate of oxygen uptake following strenuous activity. At the beginning of any workout, the body doesn’t instantly go into exercise mode. The first couple minutes or so your body can’t keep up with the exercise you are doing and as a result, the intensity of the exercise out-paces the amount of oxygen you are able to consume. This puts your body in an oxygen deficit. Eventually, if the exercise stays at a steady state, your body finds a way to consume oxygen at a regular pace. However, at some point you have to make up that oxygen deficit that was created at the beginning of your workout. You make up this deficit after you finish exercising – and this is EPOC.
So, why is this important?
After a workout, the amount of oxygen consumed can stay elevated for minutes or hours, depending on the intensity. The higher the intensity of an activity, the more oxygen will be consumed. Exercise that consumes more oxygen burns more calories.
Before, I said that if your workout stays at a steady state (like jogging, biking, and other standard aerobic activities) you only have to make up the oxygen deficit that was created at the beginning of the workout. This should only take a few minutes. But, if you are doing anaerobic, or higher intensity exercise, it will take longer for your body to recover. This is because your workout never allowed you to consume a steady rate of oxygen.
A lack of oxygen during exercise = A higher oxygen deficit
EPOC is influenced by the intensity, not the duration, of a workout. The more intense the exercise, the bigger and longer-lasting the EPOC values will be.
Think about how you feel after a challenging HIIT session. You likely continue breathing heavily for a minute or two post-workout. That’s good! That’s normal. That’s EPOC. Activities like HIIT, weight lift, circuit training, and plyometrics result in high EPOC values.
Now think about how you feel after stepping off the elliptical, you probably don’t stay winded for very long. Lower intensity activities don’t have as high EPOC values. Aerobic exercise burns a good amount of calories during the workout, but oxygen levels and calorie burn return back to normal fairly quickly after those workouts.
So, higher intensity exercise leads to a high energy demand (calorie burn) during exercise and high oxygen consumption (which results in calorie burn) post-exercise. If you were working hard enough, this elevated oxygen consumption could last throughout the entire day. That’s a lot of calories burned as a result of one workout.
Aside from HIIT, and other obvious high intensity workouts, resistance training can end up creating high post-exercise oxygen consumption as well. Resistance training is actually found to be more effective at raising EPOC than steady state cardio. This proves that lifting heavy weights really does improve more than just strength.
What should you take away from this?
That heavy breathing, exhausted feeling you have after an intense workout is not a bad thing. In fact, it’s really good. Staying warm and consuming more oxygen post-workout means that your body is continuing to burn calories. Your metabolism “speeds up” because it is able to carry on making and using energy in the body long after the workout is finished. When all is said and done, EPOC means you are burning more calories.