Personally Fit now offers a class called Afterburn. This class is only a half hour and takes place during lunch time so that people can participate during the work day. One of the goals of this class is to continue to burn calories after the class has ended. How is it possible to continue to burn a substantial number of calories after a workout is already completed? It is because of a phenomenon called excess post-exercise oxygen consumption (EPOC).
EPOC is a term used to describe the increased oxygen uptake during the recovery period of an exercise.1 The body is constantly trying to maintain homeostasis, a state of equilibrium, so in order to return to a “normal” state, the body will need to burn energy to get there. Therefore, EPOC contributes to the energy expended during a workout causing you to burn more calories after the workout has ended.1
The intensity of the session is the main factor to contribute to the magnitude and duration of EPOC. The higher the intensity, the higher EPOC, the more calories burned. Studies have shown that exercises done to fatigue tend to result in a greater and more sustained EPOC than those not performed to fatigue.1
One study looked at the difference in EPOC after a continuous bout of aerobic exercise (ex. Cycling for 30 minutes) and sprint intervals on a cycle ergometer. A cycle ergometer is a bike that you can pedal but does not move (like those found in gyms). For this study, the continuous exercise bout consisted of riding a cycle ergometer for 30 minutes. The sprint intervals were three all-out 30 second bouts with four minutes of rest in between. Therefore, the actual exercise time for the sprint intervals is only one and a half minutes. The study found that, even though the continuous exercise lasted much longer, the sprint intervals burn more calories in the end. In fact, EPOC was a whole 34% higher; meaning that the participant burned approximately 34% more calories.1 This is because the intensity was so much higher. Previous research has shown that more calories may be burned during the continuous exercise session compared to sprint intervals, but, because of EPOC and the body’s homeostatic nature, sprint intervals will result in a greater net caloric expenditure at the end of the day.1 While increasing the duration of the exercise will increase EPOC and therefore energy expenditure, increasing the intensity of the exercise will account for a greater percent increase in EPOC.3
EPOC also occurs during resistance/strength training as well. One way to prolong energy expenditure is to have smaller rest intervals between sets.2 However, you need to do this with caution. Make sure to recover enough to complete the set before starting. Another study showed that high-volume resistance training and high intensity interval aerobic training creates a higher energy expenditure after the workout for up to 21 hours when compared to continuous exercising. At the 21-hour mark post-exercise, the resistance training and high intensity training were still burning about 12 calories/hour more than the continuous exercisers.3 This could add up to be more than 300 more calories burned per day!3 However, all this good news comes with a disclaimer: as you become better trained, the caloric expenditure post-exercise will decrease. All the more reason to continue to push yourself and work above and beyond your goals!
This is part of the reason why high intensity interval training is so popular. You are able to burn a great deal of calories in a shorter amount of time, and this is what makes Afterburn such a great class especially if you are looking to lose weight. See you in class!
- Townsend, J., Stout, J., Morton, A., Jajtner, A., Gonzalez, A., Wells, A., . . . Cosio-Lima, L. (2013). excess post-exercise oxygen consumption (epoc) following multiple effort sprint and moderate aerobic exercise. Kinesiology, 45(1), 16-21.
- Miskowiec, R. W., Scott, M. C., & Nelson, A. G. (2015). Rest interval effects on prolonged epoc: 2395 board #142 may 29, 9. Medicine & Science in Sports & Exercise, 47, 644. doi:10.1249/01.mss.0000478474.53932.c1
- Greer, B. K., Sirithienthad, P., Moffatt, R. J., Marcello, R. T., & Panton, L. B. (2015). EPOC comparison between isocaloric bouts of steady-state aerobic, intermittent aerobic, and resistance training. Research Quarterly for Exercise and Sport, 86(2), 190-195. doi:10.1080/02701367.2014.999190