EPOC Effect: Everything you Need to Know

The EPOC effect consists of an increase in the number of calories we burn while resting after high intensity exercise. It could be an interesting tool to accelerate fat burning.
EPOC Effect: Everything you Need to Know

Last update: 19 December, 2019

When we want to improve our physical condition and the way we look, one of the main goals is to reduce our body fat percentage. To achieve this, it’s important to follow an adequate diet and maintain a calorie deficit. But there are a great number of other possible strategies that we can follow. In this article, we’ll talk about the EPOC effect, and how it could help to accelerate fat burning.

EPOC effect or afterburn

In this context, EPOC means ‘excess post-exercise oxygen consumption’. Therefore, it refers to the excess of oxygen that we consume after working out.

It’s also known as afterburn. This is because it elevates the basal metabolic rate, the number of calories that our body burns while resting.

The physiology of the EPOC effect

The EPOC effect, as its name suggests, begins after we perform physical activities. It causes the body to increase its energetic expenditure in the hours after exercising. This is due to the stress that we put our bodies under during the workout.

The EPOC effect happens in any sport modality or physical activity. However, it’s more noticeable and lasting when we practice high-intensity interval training. The foundation of the EPOC effect is the oxygen ‘debt’ that we create during high-intensity exercise.

Anaerobic routes

When we practice a sport, we can use energy that comes from different metabolic routes. On one side, we have aerobic routes that use oxygen.

On the other side, we have anaerobic routes such as phosphocreatine, phosphates, and anaerobic glycolysis. The common aspect of these last routes is that the exercise is so intense that the metabolism from the oxidation of pyruvate isn’t enough. Therefore, the body resorts to these tools as a way to maintain physical activity over the aerobic threshold.

A girl doign HIIT to boost the EPOC effect

Another thing they have in common is the fact that they produce metabolites. Metabolites are waste substances, products of anaerobic metabolism. An example of these substances is lactic acid. Lactic acid accumulates in our tissues and promotes acidosis, which is the origin of many muscle injuries.

Oxygen debt

Due to the lack of oxygen during exercise, the body goes into ‘debt’ for this substance after we finish the activity. The body will need more oxygen to counteract the acidosis produced by the intense activity.

This greater oxygen need translates into a higher heart rate, elevated body temperature, greater ventilation and a high level of hormones that are very metabolically active, such as catecholamines.

Therefore, we can conclude that the more intense our physical activity is, the greater the oxygen debt will be as well. If the oxygen debt is bigger, the metabolic rate will elevate for a longer period of time and with more intensity because of the processes that we’ve previously explained.

Exercise to boost the EPOC effect

As we can see, this ‘afterburn’ effect is very interesting when it comes to creating a training program to reduce body fat. After everything we’ve explained, we should understand that light to moderate intensity exercise won’t create a significant oxygen debt.

Long-distance running or cycling is based on aerobic metabolism; it allows us to exercise at low and moderate intensities for long periods of time.

HIIT: High Intensity Interval Training

The most interesting approach is to practice intense exercises in intervals. An example of this kind of training is HIIT or high-intensity interval training.

You can do HIIT in many ways, but it’s always about doing short exercising intervals at a very high or maximum intensity, separated by other longer resting periods.

This allows us to use anaerobic routes in the most ideal way possible during the periods in which we’re making our maximum effort. This will maximize the oxygen debt that we’re creating.

A girl lifting weights as part of her HIIT routine


Functional training or CrossFit is the exercise modality with the greatest oxygen debt and the highest EPOC effect. It’s a discipline based on the execution of constantly varying movements performed at a high intensity. The routines include very intense exercises in which we’ll use our anaerobic metabolic routes to the max.

For this reason, these sports modalities have an incredibly high-calorie burning rate, both during the session and after you’re finished. That’s how they became some of the best training strategies to accelerate fat burning.

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