Excess post-exercise oxygen consumption (EPOC)

Excess post-exercise oxygen consumption (EPOC) is also known as “afterburn” and occurs after strenuous exercise as a way for your body to build back its energy stores. It takes time for your body to replenish the energy used during exercise, so you continue to burn calories at a higher rate for 30–180 minutes after exercise. You might have experienced EPOC after completing a tough workout, remaining hot and sweaty even 20–30 minutes later. However, you won’t always know you’re experiencing EPOC since it’s more of a “background function” that continues running after exercise.

EPOC causes higher fat oxidation rates after exercise as compared to resting oxidation rates. The amount of energy EPOC uses is driven by the intensity and duration of your workout. For cardio exercise, intensities above 60% VO2max, or for at least 40 minutes, will require the most oxygen recovery with greater oxygen use as your intensity and duration of exercise increase. Heavy lifting to build muscular strength or power will use more oxygen than lower-intensity muscular endurance training.

Since both intensity and duration drive EPOC, it doesn’t necessarily matter what type of exercise you do—either continuous, moderate-intensity cardio exercise or high-intensity interval training (HIIT)—to see the benefits of EPOC. If your goal is fat loss, you can plan your workouts based on which type of exercise you prefer, as well as your schedule.

Doing 15 minutes of HIIT exercise results in about the same amount of EPOC energy use as 30 minutes of moderate-intensity cardio. If finding time is an issue, a short, high-intensity workout can be effective. If you do HIIT exercise and moderate-intensity exercise for the same amount of time—for example, 30 minutes—the HIIT exercise will cause greater EPOC energy use, leading to more fat burn.

Remember, EPOC only applies to energy use after exercise. For the same amount of time, it appears that HIIT is the same or better for post-exercise fat loss as moderate-intensity cardio. For more information about fat burning during exercise, read HPRC’s energy utilization article.

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Boutcher, S. H. (2011). High-Intensity intermittent exercise and fat loss. Journal of Obesity, pp. 1–10. doi:10.1155/2011/868305

Herda, T. J., &; Cramer, J. T. (2016). Chapter 3: Bioenergetics of exercise and training. In G. Haff &; N. T. Triplett (Eds.), Essentials of Strength Training and Conditioning (4th Edition). Human Kinetics.

Panissa, V., Fukuda, D. H., Staibano, V., Marques, M., & Franchini, E. (2021). Magnitude and duration of excess of post-exercise oxygen consumption between high-intensity interval and moderate-intensity continuous exercise: A systematic review. Obesity reviews: an official journal of the International Association for the Study of Obesity, 22(1), e13099. https://doi.org/10.1111/obr.13099