EPOC-alypse

[maverickBU]

Here's an article I put together recently on the benefits of EPOC and high intensity cardio vs. steady state cardio. I know this conflicts with the views of a lot of people here, so this should be fun!

EPOC-alypse, Part 1: The Science (http://savagelook.com/?p=13)

[Venom]

Great research, bro! I really enjoyed your writing style, too.

Absolutely, higher intensity exercise will increase EPOC to a greater extent. But the issue we proposed in our articles, is that either way, EPOC is only going to increase by a small amount no matter what you do. So most of the calories you metabolize will be during exercise itself. To quote one section of our article here, http://www.abcbodybuilding.com/Nutrientpartitioningpart41.php

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First, HIIT training is normally purported to take less time than lower intensity sessions. However, to control variables Laforgia et al. (1997) examined the effect of intensity on EPOC, while matching total work performed in each session. Participants consisted of eight male middle distance runners, who performed 30 minutes of 70 % V02 max treadmill running in condition one, and interval training in condition two. Interval training consisted of 20, one minute sprints at 105 % of V02 max. The session lasted 60 minutes, as sprints were interspersed with 2 minute intervals in which participants performed active recovery. It was found that the 70 % V02 max condition metabolized 31 extra calories over the entire nine hours following exercise, while the high intensity condition metabolized 64 extra calories as extrapolated by EPOC. This equates to a negligible 33 extra calories for the high intensity condition. Laforgia et al. (1997) suggests that a comparison of the excess calories above moderate intensity exercise ‘for the interval treatment is of little physiological significance to the energy balance of athletes because this amount of energy is equivalent to the kilojoules in only 75 ml of orange juice (1/3rd cup).’ They further conclude that ‘the major contribution of both treatments to weight loss was via the energy expended during the actual exercise. The excess post exercise energy expenditure is therefore of negligible physiological significance as far as weight loss is concerned.’

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So by doing 45-60 minutes of moderate intensity cardio, I will metabolize a greater amount of calories than someone who does 20 minutes of HIIT; including EPOC and caloric expenditure during the routine.

Further, results show that the percentage of fat utilized will be optimal around the 65% VO2 max range.

Say someone exercises for 20 minutes at 25, 65, and 85% VO2 max. And say that the total amount of calories metabolized were 100, 250, and 300 for the 25, 65, and 85% VO2 max conditions, respectively. Based on research, during the 25% VO2 max condition, 85% of the fuel probably came from fat, which would mean the person metabolized 85 calories from fat. For the 85% VO2 max condition, of the 300 calories metabolized, 75 calories of fat were also metabolized, but an additional 225 calories from carbohydrates were also metabolized. Finally, in the 65% vo2 max condition, a whopping 125 calories were metabolized from fat during the same period of exercise. This is 40% more total fat than both the high and low intensity conditions.

Overall, the main point Prez and I make is that EPOC is not going to be the determining factor for calories metabolized. Rather, what you do during your workout will be.


So does that mean that bodybuilders should not do HIT? No. We think a combination of both is optimal.

HIT has many benefits. It will improve mitochondria, VO2 max, vascularity, and other aspects to a greater extent than lower intensity cardio. So it should be included in a bodybuilders routine.

One method we suggest is to do both at the same time. High intensity training may prove beneficial if used properly. For example, its potent stimulation of whole body lipolysis during exercise leads to a rapid influx of plasma free fatty acids after intensity is lowered. In this context, it is postulated that performing a notably short, high intensity session, followed by a long duration, low to moderate intensity workout, may optimize lipid oxidation.

Great study on the low rest period times!

One issue I have with that study that is always quoted on HIT being superior to low intensity cardio, is that bodybuilders don’t just do low intensity cardio. In fact, bodybuilders are primarily high intensity athletes. So we receive the benefits that are associated with high intensity exercise.

Low intensity exercise is just meant to supplement our program. It is a great way to get rid of fat, while minimizing glycogen depletion and muscular damage.

SO WHAT IS BEST?!?

Again, I say a combo of both.

Let me know your thoughts!

[maverickBU]

Great response Venom!

I actually read the ABC article, and as usual, it is quality stuff. You'll be happy to know it popped up relatively early in my search on google for EPOC. /forum/images/graemlins/smile.gif

I do really like the idea of splitting HIIT and low intensity cardio in the same session. Its the best of both worlds, and ideal if you have the time and its fits into your recovery. I also liked how you point out that bodybuilders get plenty of EPOC from their weight training workouts alone. They don't necessarily follow excessively short rest periods, but they are certainly intense enough to create that "after burn".

The thing really got me leaning towards EPOC and HIIT were the more recent studies that pointed to the length of time EPOC is a factor, particularly the one I highlighted at the end, Schuenke in 2002. If EPOC can last up to 38 hours, then the Laforgia study was short-sighted, and possibly missed a much larger overall caloric effect. Also, consider the cumulative effect. With sessions intense enough to generate that length of EPOC, it will be raised to an even more significant level by overlapping sessions. I think its this cumulative effect that holds the real "blast furnace" metabolic effect.

[Venom]

That is a very good point you make.

I don't think EPOC should be ignored. As you know, everything is additive in this sport, and even 20 calories more a day can make a difference when you add that up over months.

Good article! Please post more as you write them up. /forum/images/graemlins/smile.gif

[juppy]

where is part 2?

[maverickBU]

Its coming, hopefully before I go to the Caribbean tomorrow, otherwise it'll be out sometime in the middle of July.

[lifting5]

Great article Mav, and as Venom stated above, I'm a fan of your writing style as well! I'm not familiar with EPOC, but after reading that, I'll be waiting the release of your second article.

BTW, enjoy your vacation!

[Venom]

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I'm not familiar with EPOC,

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It means excess post exercise oxygen consumption. Oxygen is an indirect measurement of caloric expenditure. If you are consuming more oxygen, it is infered that you are metabolizing more calories (about 5 calories per liter of oxygen consumed).

Right after exercise, EPOC is attributed to clearing wastes such as lactic acid, and prolonged effects of EPOC lasting up to 48 hours are attributed to increased thermogenic hormones such as T3, and catecholamines.

Here is a quote from the aforementioned article explaining.


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The Effect of Exercise Intensity on EPOC

It is well established that exercise increases oxygen consumption for several hours after its completion (Gaesser and Brooks, 1984). As discussed, oxygen consumption is used to assess caloric expenditure. Therefore elevated levels of 02 consumption reflect a higher resting metabolic rate. Explanations for such a phenomenon are connected to a number of historical events. It all began with Berzelius, who in 1808 found that lactate concentration was increased in ‘ the muscles of hunted stags( Gladden, 2004)’ who relied on anaerobic pathways to attempt to escape their predators. This was followed by Myeroff’s (1920) discovery that glycogen served as a precursor for lactate (Gladden, 2004). Building on this work, Hill proposed the 02 debt theory, which suggested that 1/5 of the increase in 02 consumption was used in the oxidation of lactate. This in turn provided the energy to convert lactate build up during exercise back to glycogen, thus repaying the ‘debt’ incurred through anaerobic processes. Scientists further noted that the 02 debt produced a curve that was characterized by a rapid phase of 02 dissipation, followed by a slow phase of decline. Margaria et al. (1933) called the fast phase alactacid, followed by the slower lactacid phase. The alactacid phase was postulated to account for replenishment of non lactic acid components of anaerobic energy utilization, such as the phosphorylation of free creatine to form creatine phosphate. The lactacid phase was said to replenish glycogen stores from lactate. However, Gaesser and Brooks (1984) suggested that these explanations were to simplistic and that evidence pointed to the majority of lactate being oxidized following exercise, with the remainder serving as a carbon skeleton for a number of processes of which glycogen replenishment is just one. Further, it was stated that the oxygen utilization could be linked to a number of phenomenon, including the residual effects of hormones, and increased temperature. In this historical review, Gaesser and Brooks (1984) introduced the new terms - excess post exercise oxygen consumption (EPOC) and recovery 02 to eliminate the ‘ implication of causality in describing the elevation in metabolic rate above resting levels after exercise.’

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[Adam Knowlden]

Awesome Mav! Thanks for sharing! I like the layout of your site as well.

[lifting5]

Thanks for the info, Venom! I wasn't that familiar with EPOC, but after reading Mav's article and your post, I remember learning about it a little bit in my exercise phys lab last semester.

[flowerkitty]

I usually stick to HIIT because of the "hamster on a wheel" thing. That and it burns a hell of a lot of calories if the intensity is high enough.

Doesn't running or sprinting on whatever increase mitochondrial density which then spares muscle glycogen and uses more lipids instead? So maybe that somehow contributes to the overall calorie burn?

[maverickBU]

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I usually stick to HIIT because of the "hamster on a wheel" thing. That and it burns a hell of a lot of calories if the intensity is high enough.

Doesn't running or sprinting on whatever increase mitochondrial density which then spares muscle glycogen and uses more lipids instead? So maybe that somehow contributes to the overall calorie burn?

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Depends on how hard and how long you go. Anaerobic exercise like sprinting is going to primarily use anaerobic energy systems (i.e., ATP and glycolytic). This is going to run your ATP & CP stores down and start to call on your glycolytic energy system to break down glycogen. Once you breakdown enough glycogen though, you will exceed your lactate threshold and will be forced to decrease intensity and use your aerobic energy systems, thus metabolizing carbs, fat, and protein for energy. I think this is why ABC's authors state that they think a combo of HIIT and steady state cardio may be best for fat loss.

Its my opinion though, that hitting the cardio quick, hard, and often will keep your EPOC high and burn more calories. When you break it down, its calories in vs. calories out, when proper nutrition and training are considered. I intend to do more writing in the near future after releasing Part 2 of EPOC-alypse (the writing is down, I just need to type it when i get home) about energy flux or "G flux" that encourages increased calories and activity to keep your metabolism at its absolute peak.

[President Wilson]

Consistantly HIIT workouts, either produce significant EPOC statistically, but not practically significant, or do not reach significance at all.

In our lab, we have done 3 EPOC studies over the last 3 years. One I was co-investigator on last year and it analyzed the EPOC response to interval training for 30 minutes in females. We worked them so hard that they were near fainting, with one participant actually fainting!

While our results nearly reached statistical significance, they fell short. Further, practically even though 02 consumption was elivated, it literally did not have any practical significance.

We then analyzed the comparison of the interval training to resistance training and found no significant difference between the two in EPOC.

In addition weight training is high intensity training, and would produce similar if not greater effects on EPOC then interval or HIIT training. Therefore, if you weight train already, you are really already incorporating a form of HIIT, at least in terms of the muscle fibers stimulated, temperature changes, and hormonal response, which are what causes HIIT.

[Fahsy]

[ QUOTE ]
Consistantly HIIT workouts, either produce significant EPOC statistically, but not practically significant, or do not reach significance at all.

In our lab, we have done 3 EPOC studies over the last 3 years. One I was co-investigator on last year and it analyzed the EPOC response to interval training for 30 minutes in females. We worked them so hard that they were near fainting, with one participant actually fainting!

While our results nearly reached statistical significance, they fell short. Further, practically even though 02 consumption was elivated, it literally did not have any practical significance.

We then analyzed the comparison of the interval training to resistance training and found no significant difference between the two in EPOC.

In addition weight training is high intensity training, and would produce similar if not greater effects on EPOC then interval or HIIT training. Therefore, if you weight train already, you are really already incorporating a form of HIIT, at least in terms of the muscle fibers stimulated, temperature changes, and hormonal response, which are what causes HIIT.

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How long after exercise did you collect metabolic data?

[Venom]

They measured 48-72 hours after. That is the typical standard for EPOC studies. The main differences seen are during the first 12-24 hours.

[Stian]

[ QUOTE ]
Consistantly HIIT workouts, either produce significant EPOC statistically, but not practically significant, or do not reach significance at all.

In our lab, we have done 3 EPOC studies over the last 3 years. One I was co-investigator on last year and it analyzed the EPOC response to interval training for 30 minutes in females. We worked them so hard that they were near fainting, with one participant actually fainting!

While our results nearly reached statistical significance, they fell short. Further, practically even though 02 consumption was elivated, it literally did not have any practical significance.

We then analyzed the comparison of the interval training to resistance training and found no significant difference between the two in EPOC.

In addition weight training is high intensity training, and would produce similar if not greater effects on EPOC then interval or HIIT training. Therefore, if you weight train already, you are really already incorporating a form of HIIT, at least in terms of the muscle fibers stimulated, temperature changes, and hormonal response, which are what causes HIIT.


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Is this article somewhere online? It looks very interesting. I would really like to take a look at it if possible /forum/images/graemlins/wink.gif

[huskerwr38]

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Doesn't running or sprinting on whatever increase mitochondrial density which then spares muscle glycogen and uses more lipids instead? So maybe that somehow contributes to the overall calorie burn?

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Sprinting doesn't increase mitochondrial density, if anything it decreases the amount of mitochondria. Sprinting uses Type II muscle fibers, which are characterized by low mitochrondrial density. It will increase those Type II muscle fibers, thus decreasing the proportionate amount of mitochondria.