Written by Garett Reid | NSCA, CSCS, CISSN, M.S.E.S.S
Fact checked by Sam Coleman, Co-Founder
FACT CHECKED
Is your workout providing the "afterburn effect?" You know, the type of training that continues to burn thousands and thousands of calories after you finish? There's a good chance you're not because it doesn't exist, at least not in the manner some may have you believe.
Technically known as exercise post-oxygen consumption, or EPOC, this style of training became famous in the late 1990s and early 2000s when HIIT training was all the rage.
This article will tell you everything you need to know about EPOC and why you don't need to be that concerned about it to burn calories.
What Is EPOC?
EPOC stands for exercise post-oxygen consumption. Knowing that probably doesn't help much in understanding what it really is, so let's break it down a bit more.
To understand EPOC, you need to realize two things.
- Our body loves being in a state of homeostasis; this means everything functions at a normal level that requires minimal energy to keep and maintain your body’s ebbs and flows
- The body has dozens of physiological systems that will fluctuate up and down to keep the body in homeostasis depending on the given environment it’s in.
When we train, the body’s physiological systems all go into hyperdrive to support the energy demand and change in physiology.
This can include:
- Replenish ATP stores
- Increasing body temperature
- Increasing heart rate
- Flushing out metabolic waste
- Altering your hormonal balance
- Producing sweat
And those are just a handful.
Now, imagine all of these systems are going nuts while you train. You then finish your workout and even though you're finished training, your body isn't! It will continue to work until it can bring all these systems back down to homeostasis. Plus, if you tear down your muscle, there's even more work to do with muscle repair.
This extra work requires calories, which ultimately requires more oxygen.
Therefore, your exercise post-oxygen consumption is the amount of oxygen the body requires after training to bring the body back to homeostasis.
In other words, it's the calories needed after training to repair your body.
How Many Calories Does EPOC Burn?
Have you ever heard of those claims about how an "EPOC" class workout will help you burn 1000 calories? Or you're going to "keep burning calories for 48 hours!"
We hate to burst your bubble, but these are highly misrepresented.
The total amount of calories burned during EPOC can vary widely, but there's one primary variable that controls it: intensity.
Exercising at a greater intensity ultimately requires a larger response to your physiological systems.
Therefore, once you stop, it takes longer to bring them back to homeostasis.
EPOC will be greater with exercise of greater intensity.
For example, some studies using sprint interval training at lower intensities saw an increase in EPOC for just 8 hours, resulting in an extra 85 calories burned.
However, another study used four sessions of a Wingate test. A Wingate test is simply peddling on a cycle ergometer at maximum intensity for 30 seconds.
These four sessions resulted in an increase in EPOC that lasted 24 hours, which equaled an extra 315 calories burned!
That sounds pretty impressive...but it's not as significant as it sounds which we’ll discuss down below.
What Type Of Training Is Best For EPOC?
People generally associate EPOC with HIIT or interval training. This is the only style of training that's often reported, making it seem as though HIIT training has a monopoly on EPOC. This isn't true.
If you have ever performed resistance training at a proper intensity, you know that your physiological systems are going haywire. This alone will generate an increase in EPOC.
However, resistance training is unique regarding increased EPOC as it creates a little bonus variable: muscle repair.
Muscle repair includes increased protein degradation and then increased synthesis during recovery. This extra work requires more calories!
Some researchers have taken advantage of this and performed eccentric training sessions with an emphasis on muscle damage.
One study resulted in an increased EPOC of 550 calories over 72 hours, the highest EPOC from resistance training ever reported! Other research has reported that using a 4-second eccentric could produce an extra 300 calories burned over 72 hours!
The "after burn" effect is even seen with a steady state. Obviously, there are a ton of variables that can affect the magnitude of the effect. However, some researchers suggest that 60-80 minutes of steady state at 70% could result in an EPOC effect of 170 calories! That doesn't sound too bad! It’s not 300 but it’s a lot more than nothing!
Now, we want to be clear that every study that has measured the EPOC of HIIT, resistance training, and steady-state has shown that the effect will likely be greatest using HIIT.
So yes, HIIT will produce greater burn during post-exercise. However, this doesn't mean you'll burn more calories.
EPOC And Total Energy Expenditure
The calories burned during EPOC are only part of the equation. To calculate the total calories burned, you must account for the calories burned during the actual session as well.
For example, let's compare two hypothetical exercises:
- Exercise A has an EPOC of 10 calories.
- Exercise B has an EPOC of 100 calories.
With only this information, it's easy to conclude that exercise B is "better" because you burned an extra 90 calories post-exercise. However, when you look a little harder, you see that a person burned 500 calories during exercise A. However, exercise B only resulted in burning 300 calories. This means that exercise A burned 510 calories and exercise B burned 400 calories. And this is what’s often seen when researchers look at total calories burned.
Consider a 2016 study that compared EPOC and total calories burned across three different exercise protocols:
- Sprint Interval Training (SIT): Six 30-second sprints with 4 minutes of active recovery.
- High-Intensity Interval Training (HIIT): Four 4-minute intervals at 95% intensity with 3 minutes of active recovery.
- Steady State Cardio: 30 minutes at 80% intensity.
The calories burned (EPOC/Total Energy) were:
- SIT: 110/270 calories
- HIIT: 83/329 calories
- Steady State: 43/349 calories
As you can see, even though the sprint interval training burns 110 calories vs. the 43 of steady state, overall, steady state burns almost 80 calories more!
A common claim is that performing SIT or HIIT takes less time. However, this too is not as significant as one would think. When you perform steady-state cardio, a person can get right into it. Further, there are no resting intervals because it's steady state.
On the contrary, even though a HIIT session may only be "10 minutes", you can't just jump right into performing at 100% intensity. You need to warm up more beforehand as well as spend more time cooling down.
So, while HIIT and SIT are usually shorter, it’s not always as significant as one may think. In this study, the SIT group only performed six 30-second sprints for 3 minutes of actual work. However, when you account for the work, rest, and cool down, the total time is 23 minutes. In comparison, the total time of steady state was 30 minutes.
Getting back to calories, other studies have demonstrated this same result.
Recall the earlier mention of the study involving four Wingate tests that led to an EPOC of 315 calories. While significant, it becomes less so when compared to the comprehensive data. The steady-state group, previously described as exercising for 30 minutes at 70% intensity, had an EPOC of only 60 calories but achieved a total caloric burn of about 500 calories—185 more than anticipated.
This reinforces the importance of considering total energy expenditure alongside EPOC when evaluating the effectiveness of different training regimens.
Should I Use EPOC?
When people speak about using EPOC, we sometimes forget that it has always existed! While we just discovered its existence, lifters were benefiting from EPOC forever!
As we have seen, resistance training and steady state both cause an increase in burns long after a person finishes training.
So, you don't need to actively “use” EPOC!
We don’t need to actively search out the EPOC effect. As long as you are using appropriate intensity and pushing yourself, your body will most likely see an increase in calorie burn after exercise.
How To Use EPOC
Ok. Let's say you know the reality of EPOC but still want to try and benefit from it; what can you do?
- Well, we know that EPOC increases dramatically with intensity and we saw numerous studies that used 30-second sprints to elicit significant EPOC.
- Therefore, continue your normal training as normal. Then, once you're finished, you could perform a couple 30-second max effort sprints or cycles. In this situation, you’ll already be warmed up so you can jump on a treadmill, bike, or rowing machine and get to it quickly! There's no need to make it any more complicated than this.
- Another option could be to perform a set of eccentric training at the end of each exercise. The study that produced 550 EPOC calories over 3 days used a 4-second eccentric, so that's a good place to start. For example, let's pretend you usually perform the bench press using a 3X5 rep scheme with 225 lbs. Do that and then perform one more set focusing on the extended eccentric phase. You could adjust the load but you get the idea. Plus, if it doesn’t increase EPOC, the worst thing that’ll happen is you’ll build more muscle!
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Bottom Line On EPOC
EPOC is yet another cool function of our body that has been twisted and misrepresented to help sell classes and programs. Yes, EPOC does exist. However, when we examine the details, we realize that any benefits from purposefully manipulating EPOC are minimal.
Even though the effects have been highly exaggerated, it does not mean typical "EPOC" workouts are bad! Performing sessions such as HIIT have many other benefits with or without EPOC. The same thing can be said about steady-state and resistance training. EPOC is there, but you should not build your workouts in an attempt to maximize its effect. Rather, just think about it as a nice, little bonus.
Read this next: Steady State vs HIIT, Which is Best for Fat Loss?
Garett Reid
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