The afterburn effect, formally known as the Excess Post-Exercise Oxygen Consumption (EPOC) is an increased rate of metabolic function following a bout of strenuous exercise, which essentially causes a greater amount of calorie burning even after the workout has been completed.
During recovery from an intense workout, excess oxygen is used to restore the body to its natural resting state through balancing hormones, replenishing fuel stores, repairing cells and anabolism of tissue. This requires the use of extra energy and subsequently an increase in the body’s metabolic rate, allowing the body to continue to burn calories until the “oxygen debt”, which builds up during exercise, has been replenished.
The afterburn effect is greatest as soon as intense exercise has been completed and slowly depletes over time, usually a period of 24 hours or so, allowing you to maximize the results of your exercise program. Several studies indicate that there is a direct correlation between the intensity of an activity and the amount of calories burned post exercise.
In one study, subjects engaged in 45 minutes of vigorous exercise through cycling and burned an average of 519 calories. But in the 14 hours after the exercise was completed, they burned an extra 190 calories more than they would have on a day where no exercise was performed. Other studies carried out at different intensity levels have shown that exercises at intensities of above 40-50% of VO2 max are necessary to trigger the metabolic processes responsible for the afterburn effect, and past this point the EPOC increases exponentially.
So what exercises are the best for maximising the afterburn effect? As mentioned already, the heart rate needs to be high in order to see any kind of noticeable increase in metabolism – meaning that you’ll need to be working seriously hard.
Light jogs or walks simply aren’t going to do the job. Optimal levels of post exercise calorie burn occur when exercise is performed at around 80% of an individuals maximum heart rate, and longer workouts also increase the effect.
One of the best types of training to achieve this is High Intensity Interval Training or HIIT. This workout overloads the body with short, very high intensity bursts, alternating with periods of low intensity “rest” sessions. It can be performed on any cardio machine such as a treadmill or rowing machine, and usually consists of a 30 second all-out sprint at maximum intensity, followed by 60 seconds of a low speed jog, alternating repeatedly for around 20 minutes or so.
Circuit training is another type of high intensity workout, which can initiate the afterburn effect. It consists of several different compound movements performed consecutively without a rest in between.
A typical circuit would consist of bodyweight squats, push-ups, pull-ups, step-ups, and abdominal crunches. You would perform 10-12 reps of each individual exercise and only rest when the entire circuit is completed, and then repeat the circuit again 3-5 times.
The key to activating the afterburn effect is always to keep the intensity and the heart rate as high as possible, allowing you to effectively lose fat well after the workout has been completed.