We all know that exercise makes our bodies use more calories than when we rest. The idea that this increased calorie use continues even after exercise is called the ‘afterburn’. Is it true that we keep burning calories even after we stop exercising?
The proper name for the afterburn is Excess Post-Exercise Oxygen Consumption or EPOC. The alternative name of ‘oxygen debt’ gives a better clue to what is going on.
Exercise raises the demand for oxygen from the muscles. Using oxygen consumes calories, so a higher oxygen demand uses more calories.
Your pulse and breathing slow to normal after your workout, but the muscle cells still need to regenerate themselves. To do this, they demand more oxygen than normal even when the exercise has ceased. That’s the afterburn effect.
When we exercise, the body initially requires oxygen at a higher rate than it can be supplied by the lungs. This is called anaerobic exercise, such as the short burst high demand of high Intensity Interval training.
Anaerobic (‘without oxygen’) exercise actually uses fewer calories than aerobic or cardio exercise, but is better for building muscle strength. When the workout is over, the oxygen needed for strengthening and healing demands calories. The body is also rebuilding glycogen stores, again demanding calories. So the afterburn definitely makes sense.
Here comes the less good news. For real scientific validity, studies of the EPOC effect would have to be carried out on thousands of people. This is not practical, but the small scale studies are all pointing to similar results. The actual increased calorie demand is 100-200 calories at best, even with a very intense workout.
Most people will be exhausted after a very heavy workout, and also quite hungry. These two effects easily offset the small extra calorie demand. So don’t overdo the post-workout treat!
Conclusion? The afterburn effect is real, but it is very small. Carry on with your exercise, and regard the afterburn as a tiny bonus.
All I know is that I'm starving after a workout and I also feel like eating very healthy food, so that's going to help my post-workout calorie count more than anything.
majorly eye-catching headline there! Good to know it is real - but I'm not surprised to find out how small the effect is. Oh well...