As we continue our study on metabolism myths, today we focus on EPOC. If you read our last post, which focused on trying to raise metabolism through exercise, you already know that EPOC is Excess Post-exercise Oxygen Consumption – or the amount of oxygen required after your workout.
If you jump on the elliptical machine first thing in the morning and turn that walk into a fast jog, or an even faster run, you require more oxygen. When your workout is finished, your body is still using more oxygen than had you skipped your workout and simply opted to watch Saturday morning cartoons in bed.
While we know that EPOC most definitely increases the need for oxygen after exercise, there’s a general misunderstanding that we need to set straight.
Myth #4: EPOC increases metabolism by burning more calories all day long after exercise
There’s a rather unfortunate myth floating around that the oxygen requirement of EPOC will ultimately translate into a higher metabolism. It kind of makes sense, and it might even be easy to understand how this myth came to be so prevalent.
After a hard workout, you’re breathing harder, your heart rate is elevated for a while – you’re burning more calories. Doing this over and over again would surely translate into an elevated metabolism, right?
Unfortunately, burning more calories through exercise has nothing to do with metabolism being increased. It’s just a normal part of the physiological processes our bodies engage in when activity is increased.
But the science behind EPOC is why the metabolism myth is perpetuated. There have been numerous studies done on EPOC and those studies vary in the amount of reporting of excess oxygen needed, but they all report average values from 6 to 14% – for individuals in poor to average shape.
For our math, let’s use an average of 10% to see just how substantial EPOC is for adding to our daily calorie burn.
To get the 10% (or above) benefit of EPOC, you have to be pushing it pretty hard. Light jogging isn’t likely to get you there unless you’re completely out of shape. If you spend 40 minutes on the treadmill and burn 600 calories, that’s an extra 60 calories burned post-exercise. That’s not too terribly bad. After all – it all adds up, right?
It’s just that it’s not significant for the amount of work you just put in. 600 calories in 40 minutes is pushing it hard. Had you just chose to workout less strenuously and burn 600 calories in an hour, your EPOC might have only been 5% – for a net difference of 30 calories post-exercise. That’s not many extra calories for all that maximum effort and pushing your body to the limit.
Unfortunately, this number drops significantly more as you get in better shape. Studies have shown that EPOC was as low as 1% for trained athletes. Bummer.
This makes sense when examining it more closely. As we pointed out in yesterday’s post, as you become more fit, you simply don’t require as much oxygen and your vitals all return to baseline much faster. It stands to reason that Usain Bolt wouldn’t be burning many post-exercise calories after running a mile, even at maximum effort. His breathing and heart-rate would return to normal in minutes.
HIIT and EPOC
The harder you train, the more calories you burn and research validates that engaging in HIIT exercises will result in a greater demand for oxygen post-exercise – but just how much?
Returning to the above example with Mr. Bolt, it’s evident that even though he won’t be burning nearly as many calories as you or I will when running a mile, he’s still burning more at a fast sprint than a slow jog.
If a trained athlete burns far fewer calories while training (because metabolism is more efficient), then it stands to reason that he’ll most certainly be burning fewer calories when watching TV (compared to an untrained person).
This is an important distinction to understand. While HIIT improves fitness and helps to burn calories and body fat, the EPOC variable is minimal as you progress with your fitness goals.
Athletes are able to eat enormous amounts of food because they engage in enormous amounts of exercise to burn it off – not because they have super-human metabolisms that require thousands of calories more than the average person. Seen those NBA stars on TV a few years after retirement?
If you’re considering sprinting or other HIIT exercises in the hopes of burning more calories post-exercise, you will get a marginal reward. Alternating between intense/non-intense sprints for 30 minutes will typically burn about 100 calories more in that half-hour span and if we use our above average of 10% again, that’s an extra 10 calories post-exercise for all of your hard work. As you become better trained, expect less.
If you’re considering HIIT for raising metabolism, we would encourage you to read yesterday’s post on raising metabolism with exercise. Unfortunately, that simply doesn’t happen.
If you want to get the best bang for your buck with cardio, add a wide variety of exercises to your workouts. You’ll keep hitting different muscles, improving body composition, while keeping your body from adapting to your workouts – thereby burning more calories.
Burning calories works best during exercise – not after. EPOC, unfortunately, is going to do little in burning excess calories and it certainly isn’t going to raise your metabolism.