We’ve all seen late night TV infomercials where they are marketing an exercise DVD which boasts grossly exaggerated claims that boot camp cardio or circuit training workouts are going to magically give you this Herculean afterburn effect and that the afterburn is going to be in the 1,000 plus calories after each workout.
The afterburn effect after an intense workout will never be greater than the calories you burned during the actual workout whether it is cardio or weight-training or both. If it was, everybody in our society who exercised would be in great shape.
I’ve seen guys with Doctorate and Masters degrees in Exercise Science as well as huge fitness marketing companies push this ridiculous afterburn theory which the science clearly contradicts.
What is EPOC? It stands for Excess Post-Exercise Oxygen Consumption also known as the afterburn effect. When you exercise your body at high intensity levels and then stop the workout, your body is still hot and takes time to cool off. The amount of oxygen it takes to get your body back to its normal resting level is what happens during EPOC, aka the afterburn effect. And it is during this phase when your body is going from hot to warm and back to normal that you are burning those post-workout calories.
A good analogy would be driving your car for 3 hours and then pulling over to the side of the road for a an hour or so. At this point, your engine is really hot and is going to take some time to cool down to resting temperature. This is what happens to your body after an intense exercise session and it is during that phase – the EPOC phase – that you are burning calories after your workout.
The truth of the matter is that the calories you are burning post-workout will never be greater than the calories you burn during the workout itself. The average afterburn effect is anywhere from 6 to 15% of your total calories burned. Now does that even sound like a lot? Not really but think of it this way – if you do this over an 8 or 12 week period, then it begins to have a significant cumulative effect.
Let’s say you burn 600 calories after an intense workout. Well 10% of that is 60 calories, which might be your typical potential afterburn effect. As I said earlier that might not seem like a lot but if you add up all those extra 60 afterburn calories over an 8 or 12 week period then it starts to add up.
It’s important to understand that the duration of the workout doesn’t influence EPOC. It’s the intensity which counts. Research shows that heavy weight resistance training and HIIT – High Intensity Interval Training – can produce a bigger EPOC effect than, for example, running at a steady state rate.
A study done in 2003 compared two exercise groups. The first group did aerobic cycling for 40 minutes at 80% max HR and 4 sets of circuit training of 8 exercises for 15 reps at 50% of their 1 rep max. The second group did heavy resistance training exercise for 3 sets of 8 exercises at 80 to 90% of their 1 rep max to exhaustion. The study showed clearly that the heavy resistance training group produced the greatest EPOC effects.
So when you are working out and your goal is to increase or heighten your EPOC – afterburn – caloric effect then you should be mindful of heightening the intensity of your workouts and increasing the load of what you are lifting. The science says that this will give you the greatest calorie burn after you work out.
Bersheim, E. and Bahr, R. (2003). Effect of exercise intensity, duration and mode on post-exercise oxygen consumption. Sports Medicine, 33, 14, 1037-1060
LaForgia, J., Withers, R. and Gore, C. (2006). Effects of exercise intensity and duration on the excess post-exercise oxygen consumption. Journal of Sport Sciences, 24, 12, 1247-1264.