The Exercise Afterburn Effect

The Afterburn Effect; Burn Calories While Doing Nothing!

What Is The Afterburn Effect?

- Exercise after-burn, also know as excess post-exercise oxygen consumption (EPOC), is when the body continues to burn calories after the exercise session is over. For example, let's say you go for early morning jog for 30 minutes. After you have finished the 30 minute jog, your body will continue to burn calories for the next 15 minutes to 48 hours! EPOC represents the amount of oxygen consumption needed to bring the body back to a pre-exercise state. The amount of calories burned from EPOC is directly related to exercise intensity and duration. The harder and longer you exercise, the more calories your burn via the exercise after-burn!

Exercise Intensity!

- Exercise intensity, according to all the studies conducted to date, is the most important determinant of the effect of EPOC. The harder and more intense you exercise, the greater the effect of EPOC is.

In a study published in the European Journal of Applied Physiology and Occupational Physiology, the effect of exercise intensity on EPOC was studied in 8 trained men and 8 trained women. The subjects were examined after completing 3 separate exercise bouts of different intensities. The intensities were 40%, 50%, and 70% of their VO2 maxes. Your VO2 max is the greatest amount of oxygen your body can take in and use for exercise. Your VO2 max is a good measure of your fitness level. The more oxygen you are able to use, the more energy you will be able to create, so the higher your VO2 max, the higher your fitness level is. 

 

So let us get back to the study. The study showed that the intensity levels had a great effect on the duration of EPOC. In both men and women, the effect of EPOC was greater as intensity increased. 

The study also showed that even low levels of exercise intensity still have a positive effect on EPOC. The results of the study were as follows:

- For the men

40% VO2 max - EPOC was 31.2 min;

50% VO2 max - EPOC was 42.1 min;

70% VO2 max - EPOC was 47.6 min

- For the Women

40% VO2 max - EPOC was 26.9 min;

50% VO2 max - EPOC was 35.6 min

70% VO2 max - EPOC was 39.1 min

In another study published in the Journal Of The American College Of Nutrition, the effects of low and high intensity exercise on calories burned during exercise and after exercise were studied in 8 active women, ages 22 to 31. Although both groups burned 500 calories, the effect of the exercise after-burn was much greater for the high intensity group (45 extra calories) versus the low intensity group (24 extra calories).

Effect Of Duration On EPOC!

Duration also has been shown to play a big role in the energy after-burn effect. In one study conducted in 1988 published in the Canadian Journal of Sports Science, subjects were divided into 3 groups.

Although all three groups exercised at 70% of their VO2 max, the duration was different for each group. One group exercised for 3o minutes, another group for 45 minutes, and the final group exercised for an hour. The results of the EPOC values of the studies were 33 calories lasting 128 minutes, 74.5 calories lasting 204 minutes, and 165 calories over 455 minutes for the durations of 30, 45 and 60 minutes, respectively. This study showed that increasing exercise duration has a great effect on EPOC.

 

In another similar study (1), 6 healthy male subjects exercises at 70% of their VO2 max for 80 minutes, 40 minutes, and 20 minutes. The results of EPOC were 55.5 calories, 73.5 calories, and 159.5 calories for 20 minutes, 40 minutes, and 80 minutes respectively.

There have also been studies that have combined high intensity exercise with longer durations.

There are more studies such as these that show similar effects of duration's effects on EPOC. In a study published in the European Journal of Applied Physiology and Occupational Physiology, 8 trained males performed 164 minutes of treadmill running at 70% of their VO2 max. The average EPOC effect was 162 calories, which is a significant contributor to overall energy expenditure.

So it's pretty simple then, right? Just exercise harder and longer and you'll burn more calories from the exercise after-burn! Unfortunately, that may not be entirely correct. There have been studies that show different exercise after-burn effects from exercise. Some studies showed a low EPOC effect after exercise of long and short duration even with high intensities. From all the research done, the effect of EPOC varies from person and person. It seems that many factors such as gender, age, fitness level, etc. may be playing a role in the effect of EPOC.

Interval Training!

If you really want to maximize your calories burned from the exercise after-burn, the I would highly recommend performing intermittent training, which is a form of interval training. Intermittent training consists of shorts bouts of all out exercise followed by a rest period. You would repeat this over and over throughout the course of the workout. The Fields Sprints workout video is an example of an interval training workout.

A study published in the Journal of Applied Psychology consisted of 8 males performing 20 1-minute intervals at 105% VO2 max with corresponding 2 minute rest periods between intervals. The same 8 males also performed 30 minutes of continuous exercise at 70% VO2 max to allow for comparisons. The results showed a significant increase in the EPOC effect for the interval training (75 calories) versus the continuous running (34.5 calories).

Resistance Training!

So we have pretty much covered everything about the exercise after-burn effect on cardiovascular exercise, but what about strength training?!

Although it is difficult to compare cardio to resistance training because of just the sheer difference of the type of workout and exercise intensity, there have been studies trying to compare them.

In a study published in the Journal of Applied Sport Science Research, the subjects were broken down into 3 groups. One group performed 40 minutes of cycling at 80% of their maximal heart rate. Another group performed 40 minutes of circuit training (50 percent of individuals' maximum lift [1 RM] x 15 repetitions x 4 sets) and the final group performed 40 minutes of heavy resistance lifting (80 to 90 percent of 1 RM x 3-8 repetitions x 3 sets). Heavy resistance training produced the greatest EPOC ( 53 calories) compared with circuit training (51 calories) and cycling (33.5 calories).

So what did we learn from all this? 

To exercise! More important than any of the details of the exercise afterburn is the exercise! Find something you enjoy doing and do it! Above all else, just make sure to exercise and be active. If you really want to maximize your training program and burn the most calories from the exercise after-burn response then I would recommend doing the following:

Tempo Training:Continuous aerobic exercise at a high intensity for half an hour to an hour.

Long, Slow Distance Training:Continuous aerobic exercise at a moderate intensity for an hour.

Split Training:2-4 high-intensity exercise bouts for a period of 15-25 minutes with a 5 minute rest in-between.

Continuous Interval Training:Alternating 3-minute bouts of low-intensity and high-intensity exercise for a period of 30-60 minutes. An example of this would be to walk for 3 minutes, then jog for 3 minutes, then walk for 3 minutes, etc. Or if you are in very good shape, you would jog for 3 minutes, sprint for 3 minutes, jog for 3 minutes, etc.

Supramaximal Interval Training:15-20 of really high intensity exercise (the hardest you can exercise) for a period of 1 minute, with 2- to 5-minute rest periods in-between.

Heavy Resistance Training:2-4 sets, 8-10 exercises, 3-8 reps of 80%-90% of your 1-rep max with 2- to 3-minute rest periods

 Source : Danny Maman