Burn It: Train to Achieve the EPOC

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EPOC Your Way to Torching Calories

You’ve probably heard about the “afterburn.” Most of the time it is explained like this; it is the continual burn of calories after a very high intensity workout: hence the afterburn. This sounds literally too good to be true. I mean can you really keep your metabolism ramped up long after your workout is over? If you are like me, you try to maintain a high intensity every single workout, but is it enough to induce an afterburn? Let’s dive into the science to figure out the truth behind the afterburn effect.

Afterburn = EPOC

Burn It- Train to Achieve the EPOCNowadays the afterburn is referred to as Excess Post-Exercise Oxygen Consumption (EPOC). In layman’s terms, EPOC is the amount of oxygen consumed after a workout to return the body to its resting state.

It is widely accepted in exercise physiology that for every liter of oxygen consumed you burn 5 calories, so the more oxygen consumed after a workout the more calories burned (Vella & Kravitz 2004).

This metabolism increase is due to oxygen replenishment, energy re-synthesis, lactate disposal… etc (Schuenke et al 2002).

The increased rate of oxygen consumption that it takes to accomplish all of these tasks is exactly what EPOC measures and what the afterburn is all about: demolishing calories to get back to a normal resting state (Scott & Kemp 2005).

This post-exercise calorie burn can reach levels as high as 150+ calories (exercise intensity/duration dependent); pretty significant caloric burn while just resting after a workout (Bahr & Sejersted 1991).

After a great workout when the sweat is pouring, you can barely catch your breath, and your muscles are so pumped they might pop (you’re in beast mode), it’s understandable that it can take a lot of energy to return you to your normal resting state!

Increasing your EPOC is a great workout goal but if it only lasts a couple minutes it might not be worth it, right?

It turns out that the EPOC effect can last minutes to days after your workout is over (depending on intensity). Immediately after your workout, your metabolism is at its highest because the body is trying to return your biggest physiological functions to normal rather quickly (respiration, heart rate, stroke volume) and your oxygen consumption is at its highest.

Over the next several hours your body is still consuming more oxygen and expending more energy than normal to return to equilibrium (Schuenke et al 2002).

For instance, the Bahr & Sejersted (1991) found that there was a significant EPOC effect at least 10.5 hours after the workout! Get this though; one study found that there was a significant increase in the metabolic rate 38 hours after an intense workout (Schuenke et al 2002) and possibly 48 hours (Vella & Kravitz 2004)!

So it seems there is a significant calorie burn long after your workout is over. This should make your wonder, “How in the hell do I ramp up this EPOC magnitude?

How Is EPOC Affected by Exercise Intensity?

Here comes a no brainer: a higher intensity workout will reward us with a greater EPOC magnitude directly after a workout (especially within 20 minutes; Thornton & Potteiger 2001) and hours after the workout (Borsheim & Bahr 2003).

For example, it was found that performing strength training at 85% of your 8 rep max produces a significantly higher EPOC magnitude than strength training at 45% of your 8 rep max (Thornton & Potteiger 2001).

Likewise, a study by Bahr and Sejersted (1991) found that performing an exercise at 75% VO2max (VO2 max = maximal oxygen consumption or uptake per minute; here are a couple ways to calculate your VO2 max, actual measurement requires laboratory equipment) compared to VO2max of 50% for the same amount of time elicited a larger EPOC response!

Clearly high intensity is the way to go if you want to increase EPOC (Warren et al 2009)!

How Is EPOC Affected by Exercise Duration?

While exercise intensity is important in inducing a significant EPOC magnitude, recent research says that when exercise expenditure is the same, exercise duration is equally as important (Malatesta et al 2009). One study determined that the participants who walked at 70% VO2 max for 60 minutes had a significantly higher EPOC compared to the participants who only walked 20-40 minutes (Quinn et al 1994).

This seems to be the norm when it comes to the magnitude of EPOC; the longer you perform the exercise at a high intensity the larger the EPOC magnitude.

This can become a predicament because we all want to increase our calorie burn but many of us do not have the time or the stamina to carry out these exercises for such an extended period. You can still get a significant EPOC effect after your workout with shorter training methods!

While the EPOC effect was higher for the longer exercise duration in the Quinn and associates (1994) study, those that performed the exercise for 20 and 40 minutes still achieved calorie burn after their workout was over! In fact, although the participants only exercised 1/3 the time (20 minutes) compared to long duration exercise group (60 minutes) they still achieved over half of the EPOC effect (57%).

There is a tradeoff between the time allotted to exercise and the amount of EPOC you want to achieve; it’s unique to your situation.

What Type of Training is Best to Increase EPOC?

EPOC WeightsCompared to other training methods, resistance training has been found to produce the greatest afterburn response (Elliot et al 1992; Gilette et al 1994). Resistance training gets your larger muscles active, energy reserves drained, your blood pumping, and lactic acid building up which can take a long time to remove.

Not only has it been determined that resistance training is the best way to increase EPOC it has also been found that within resistance training, circuit training is the best method.

Compared to typical resistance training, circuit training significantly increases EPOC (Murphy & Schwarzkopf 1992)! This can be attributed to the intermittent nature of circuit training in which participants only rest 30 seconds or less between sets, while performing normal resistance training participants usually have longer rest periods (over 120 seconds; Murphy & Schwarzkopf 1992).

Less rest means the body stays highly strung and doesn’t give it a chance to return to its normal resting state, keeping our physiological processes in overdrive.

If you still prefer to do cardiovascular training (e.g. running, biking, elliptical), it has been found that intermittent training increases EPOC significantly more than stead-state training (Kaminsky et al 1990; Laforgia et al 1997)! For instance, Kamnisky and associates (1990) found that running in an interval training fashion (two – 25 minute runs at 70% VO2max) elicited a significantly greater EPOC response than a single steady-state bout (50 minute at 75% VO2max).

You can greatly increase you EPOC by implementing bouts of high intensity interval training into your continuous exercise regime!

Putting Science Into Action

Unless you have a significant amount of time on your hands, we need an effective way to ramp up the afterburn to get us burning calories possibly 38 hours post-workout (Schuenke et al 2002) in a timely manner. From the majority of the scientific research on the subject, we can conclude at least four key variables that you need to implement in your EPOC increasing workout:

  1. Perform exercise at a high intensity (70 – 75% or your VO2 max or 85% of our 8 rep max)
  2. Perform for at least 30 minutes
  3. Perform resistance/circuit training
  4. If you insist on cardio, perform intermittent training

We need to stay at a relatively high intensity (70 – 75% VO2 max [Kaminsky et al 1990] or 85% of your 8 rep max [Thornton & Potteiger 2001]) for an extended period of time (at least 30 minutes) in order to get a significant EPOC effect for our time input.

Well that’s great and all, but it’s hard to determine your VO2max during a workout. You can use this calculator to specify your target VO2max which will tell you the corresponding heart rate to maintain (age dependent) during your exercise routine (it’s not 100% perfect but it’s a good number to shoot for; Swain et al 1994).

Also remember that resistance training can produce the greatest EPOC effect especially if you incorporate a circuit or intermittent type training method into your workout regime.

If you can combine these variables, you will have stuck the mother-load in terms of metabolic performance.

One suggested method to achieve a high-magnitude afterburn, is to super-set each exercise with an opposing muscle group so you are constantly moving from one exercise to the other, with minimal to no rest between each sets (less than 30 seconds).

This gives your workout more of a circuit training format that will get your heart pumping, you sucking oxygen, your muscles beat, and you at a high-intensity during the entire workout!

If the exercise doesn’t feel taxing or hard enough, then it probably isn’t and you should increase your intensity.

When it comes to such a high intensity workout that can have affects up to 48 hours later, it’s only recommended that you perform these workouts 2-3 times a week due to the toll they can take on your body! This will give your body plenty of time to recoup, recover, and grow between workouts.

By incrementally increasing your EPOC, you will start to see results as the total calorie burn starts to add up!

Wrap-Up

EPOC CardioIt’s amazing how the duration and intensity of your exercise regiment can affect your physiology and boost your metabolism after your workout.

While EPOC magnitude can vary between individuals, if you remember exactly what EPOC is all about and the science behind it, you can use that to your advantage and implement a fitness regime that takes that into consideration.

Although the science has been put in layman’s terms for simplicity, the fact of the matter remains that these tips can help you ramp up your metabolism long after your workout is over; demolishing calories and getting you the results you deserve!

Remember these four variables when setting up your EPOC training workout:

  1. Perform exercise at a high intensity (70 – 75% or your VO2 max or 85% of our 8 rep max)
  2. Perform for at least 30 minutes
  3. Perform resistance/circuit training
  4. If you insist on cardio, perform intermittent training

References

Bahr R, Sejersted OM (1991) Effect of intensity of exercise on excess postexercise oxygen consumption. Metabolism 40: 836–41.

Borsheim E, Bahr R (2003) Effect of exercise intensity, duration and mode on post-exercise oxygen consumption. Sports Med 33: 1037-1060.

Elliot DL, Goldberg L, Kuehl KS (1992) Effect of resistance training on excess post-exercise oxygen consumption. J Appl Sport Sci Res 6: 77-81.

Gilette CA, Bullough RC, Melby C (1994) Postexercise energy expenditure in response to acute aerobic or resistive exercise. Internat J Sports Med 4: 347-360.

Kaminsky LA, Padjen S, LaHam-Saeger J (1990) Effect of split exercise sessions on excess postexercise oxygen consumption. Brit J Sports Med 24: 95-98.

Laforgia J, Withers RT, Shipp NJ, Gore CJ (1997) Comparison of energy expenditure elevations after submaximal and supramaximal running. J App Physiol 82: 661-666.

Malatesta D, Werlen C, Bulfaro S, Chenevière X, Borrani F (2009) Effect of high-intensity interval exercise on lipid oxidation during postexercise recovery. Medicine and Science in Sports and Exercise 41:364-374.

Murphy E, Schwarzkopf R (1992) Effects of standard set and circuit weight training on excess postexercise oxygen consumption. J Appl Sport Sci Res 6: 88-91.

Quinn TJ, Vroman NB, Kertzer R (1994) Postexercise oxygen consumption in trained females: Effect of exercise duration. Med Sci Spots Exer 26: 908-913.

Schuenke MD, Mikat RP, McBride JM (2002) Effect of an acute period of resistance exercise on excess post-exercise oxygen consumption: Implications for body mass management. Eur J Appl Physiol 86: 411-417.

Scott CB, Kemp RB (2005) Direct and indirect calorimetry of lactate oxidation: implications for whole-body expenditure. J Sports Sci 23: 15-19.

Swain DP, Abernathy KS, Smith CS, Lee SJ, Bunn SA (1994) Target heart rates for the development of cardiorespiratory fitness. Med Sci Sports Exerc 26: 112–116.

Thornton MK, Potteiger JA (2001) Effects of resistance exercise bouts of different intensities but equal work on EPOC. Med Sci Sports Exer 34: 715-722.

Vella CA, Kravitz L (2004) Exercise after-burn: A research update. IDEA Fit J 1.5: 42-47.

Warren A, Howden EJ, Williams AD, Fell JW, Johnson NA (2009) Postexercise fat oxidation: effect of exercise duration, intensity, and modality. International Journal of Sport Nutrition and Exercise Metabolism 19:607-623.

Josh Anderson
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