Afterburn Effect Workouts

The afterburn effect refers to calorie burning that occurs after a workout. You'll also hear it called excess post-exercise oxygen consumption (EPOC).

This post-exercise state was originally called "oxygen debt" when A.V. Hill and H. Lupton first hypothesized it in 1922. In their view, the body entered this state in order to replace the extra oxygen used by working muscles during exercise.

Since 1922, researchers have expanded the scope of the term EPOC to include several different events that occur as the body restores itself to its pre-exercise state.

After an intense workout, not only is your body consuming oxygen at an elevated rate, it's also replenishing the phosphagen system (which supplies it with immediate energy), it's normalizing levels of circulatory hormones, and it's working to repair muscles, making them stronger and bigger than before.

This restoration process requires extra energy, which is why you continue to burn additional calories after a workout. For this reason, the afterburn effect can play an important role in an exercise program for weight management and muscular development.

So how do you go about triggering this effect? Research studies (summarized in the next section) have consistently demonstrated that the afterburn effect is largest following high intensity resistance training.

Your workout routines need to be intense enough to create an "oxygen debt," so to speak. Steady-state low-intensity exercise (e.g. walking or jogging) just doesn't do that. At the intensity required to elicit a noticeable afterburn, you shouldn't be able to carry a normal conversation because you're breathless. In other words, you're going to need to work--hard! With that said, afterburn exercises require a certain level of fitness that may not be suitable for everyone. As always, you should talk to your doctor before beginning any fitness program.

Furthermore, you should approach your training routine with realistic expectations. That the afterburn effect is not magic, you won't grow a six-pack in one-night. As with any weight loss/muscle gaining routine, you must be consistent in your training and your nutritional habits need to be conducive to your goals.

As the studies below demonstrate, the afterburn effect after each individual workout translates into only a modest amount of additional calories burned. It takes time for these additional calories add up and translate into noticeable results. But when they do add up, the results are quite impressive! See the Trembblay study summary below where subjects who followed an afterburn routine over 20 weeks lost 9x as much fat per calorie expended compared to people doing traditional aerobics.

Whether metabolism speeds up for hours after exercise is an age old question. Over the years, study after study has been carried out with mixed results. Some studies report no afterburn effect, while other studies report a substantial one. Similarly, if you visit a few fitness forums, you'll find people who firmly believe in the afterburn effect as well as those who think it's a myth.

In order to make sense of the conflicting literature, it's important to examine each study's methodology. The afterburn effect itself is difficult to measure, which is why studies often differ in what they mean by the "afterburn effect" and how they measure it. Different researchers also use different exercise routines, making comparisons between studies even more difficult.

For example, this study by Dionne et. al. had participants exercise on a treadmill at only 50% of their maximum VO2 for 1 hour (VO2 is the maximum amount of oxygen a person's body can take in during exercise). Immediately after exercise, the subjects drank a protein shake that had the same number of calories burned during the exercise. Dionne reported no afterburn effect--i.e. people who didn't exercise had the same post-exercise energy expenditure as those who did.

In contrast, the Knab et. al. study (summarized below) had subjects exercise on stationary bikes at around 70% of their maximum VO2 for 45 min. In this study, a large afterburn effect was reported. Clearly, methodology is key in determining the results of an experiment. Keep this in mind when evaluating scientific literature.

The studies below provide evidence for the afterburn effect. As I update the lens I will also provide studies that report no afterburn effect so you can make note of the differences.

A 45-Minute Vigorous Exercise Bout Increases Metabolic Rate for 14 Hours. Knab et al. Medicine and Science in Sports and Exercise. 2011 Feb 8.

Researchers had ten male subjects cycle vigorously for 45 minutes at about 70% VO2 max. During each 45-min exercise session, subjects burned an average of 519 calories. For 14 hours post-exercise, subjects burned 190 more calories than they did on a day when they hadn't exercised. In other words, subjects burned 37% more calories in the 14 hour post-workout period than during the exercise itself.

One-set resistance training elevates energy expenditure for 72 h similar to three sets. Heden et. al. European Journal of Applied Physiology. Volume 111, Number 3, 477-484, Mar 2011.

In this study, eight overweight young adults were put on two full-body resistance-training routines. Each subject completed both training routines, 1 week apart, in a random order. In one training routine, subjects would do 10 exercises, 1 set for each exercise, at a maximum of 10 reps per set. The other training routine was identical, except the subjects did 3 sets per exercise.

The researchers then examined the subjects' resting metabolic rate at 24, 48, and 72 hours after the workout. There was no difference between groups; both groups showed an afterburn effect (elevated metabolism) of around 100 extra calories per day. This suggests that intensity has a greater effect than volume in determining how many calories are burned after a workout.

Impact of Exercise Intensity on Body Fatness and Skeletal Muscle Metabolism. Trembblay A, Simoneau JA, Bouchard C. (1994). Metabolism. 43(7): 814-818.

Participants were put on a 20 week program and split into two groups: A High Intensity Interval Training Group (HIIT) and an Endurance Training (ET) group. The HIIT group performed training routines with alternating intervals of sprints and rest periods, while the ET group performed a more traditional aerobic routine. Both groups progressed in intensity.

At the end of the study, the HIIT group lost about three times as much subcutaneous fat as the ET group even though the HIIT group expended less than half as many calories. For every calorie expended during HIIT, there was a nine fold loss of subcutaneous body fat as compared to the ET group. A more detailed summary of this study with the specific workout protocol used can be found here.

Exercise After-Burn: Research Update.
By Chantal A. Vella, Ph.D. & Len Kravitz, Ph.D.
A review of EPOC and the research supporting it.

Effect of an acute period of resistance exercise on excess post-exercise oxygen consumption: implications for body mass management. European Journal of Applied Physiology. Volume 86, Number 5, 411-417.
This study found that a measurable afterburn effect could be detected up to 38 hours post-workout.

Resistance Training and EPOC
Jeff M. Reynolds and Len Kravitz, Ph.D.

Afterburn workouts typically fall in one of the following categories: 1) High Intensity Interval Training (HIIT), 2) Circuit Resistance Training, or 3) Heavy Resistance Training

High Intensity Interval Training
In this type of workout, you overload the body with short, high-intensity bursts that are separated by low intensity/rest intervals in between. HIIT is good if you get bored staying on the same machine for a long time. The most advanced HIIT workouts are usually no longer than 20 minutes.

Here's a sample HIIT session for beginners involving jogging and sprinting:

1. Warm up jog for 4 minutes


2. 15 seconds: sprint as fast as you can


3. 60 seconds: walk or rest


4. REPEAT cycle 10 more times followed by a 15-sec high-intensity blast at the end

As your endurance increases, you can lengthen your "high-intensity" intervals, and when you become advanced, you can shorten your "rest/low intensity" intervals. For example, 30 seconds sprinting + 60 seconds rest. When advanced: 30 seconds sprinting + 30 seconds rest.

HIIT is not only limited to running. You can do intervals with a jump rope, on an elliptical or stationary bike, or simply by doing jumping jacks.

Bodybuilding.com has an excellent article on Interval Training: 8-week HIIT for Fat Burning Program.

Circuit Resistance Training (aka Metabolic Training)
According to Marc Perry at Builtlean.com metabolic training is "completing structural and compound exercises with little rest in between exercises in an effort to maximize calorie burn and increase metabolic rate during and after the workout. " It is because of the constant movement, small rest periods, and high resistance that Metabolic Training will give you a good afterburn.

A sample circuit might look like this:

1. Four-count squat thrusts


2. Push-Ups


3. Scissor Step Ups


4. Abdominal Sit Backs


5. Squats to presses


6. Body weight rows

You'd complete about 10-12 repetitions per exercise and repeat the entire set 2-3 times, resting between each completed circuit.

If any of the above exercise terms are unfamiliar to you, use Bodybuilding.com's free exercise database. It has videos and guidelines on how to perform just about every weight-training exercise.

Marc Perry has an excellent free article that covers the basics of Metabolic Training as well as its benefits. It also includes a few sample workouts.

More circuit training workouts can be found on these websites:
Bodybuilding.com: Circuit Training Workout.
Military.com: 20-minute circuit workout
About.com: Secret Weapons for Weight Loss - Maximize your After-Burn.

Heavy Resistance Training
Arguably the best way to get an effective afterburn is just pumping iron at high intensity. Key phrase: high intensity. You should be lifting weights that are heavy enough so that you can only lift them 8-10 times per set Anything over that is too light. Increasing your muscle mass will allow you to continue to burn calories once your workout is complete.

Mark McManus, owner of Musclehack.com, has a free Targeted Hypertrophy Training (THT) system that is excellent for this, along with his Total 6 pack abs nutritional program.

I highly recommend the THT system, not only because it's FREE but also because Mark has done all of the tedious rep/set calculations for you. You get free workout logs (spreadsheets) that tell you exactly which exercises to do and how many reps and sets of each. Trying to figure out how many reps and sets you should be doing for maximum muscle growth can be confusing, especially in the beginning. But sticking with Mark's program will set you in the right direction.