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EPOC: Excess Post-Exercise Oxygen Consumption After Exercise

One of the primary bases upon which the superiority of HIIT is based is the idea of the calorie afterburn that occurs after training.    Technically this is called the Excess Post-Exercise Oxygen Consumption or EPOC.   Since it relates to the topic of steady state vs. interval training, I want to examine it here.

LaForgia et al. Effects of exercise intensity and duration on the excess post-exercise oxygen consumption. J Sports Sci. 2006 24(12):1247-64

Recovery from a bout of exercise is associated with an elevation in metabolism referred to as the excess post-exercise oxygen consumption (EPOC). A number of investigators in the first half of the last century reported prolonged EPOC durations and that the EPOC was a major component of the thermic effect of activity. It was therefore thought that the EPOC was a major contributor to total daily energy expenditure and hence the maintenance of body mass.

Investigations conducted over the last two or three decades have improved the experimental protocols used in the pioneering studies and therefore have more accurately characterized the EPOC.… Keep Reading

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Steady State vs. Intervals and EPOC: Practical Application

When I looked at EPOC,  I threw out a lot of data regarding the actual impact of exercise on the post-exercise calorie burn. Since that piece was on the long side to begin with, I decided to save some more concrete examples for today’s follow-up blog.

Semi-recapping from yesterday, the paper conclude that high intensity training can generate larger EPOC’s at least in terms of the percentage contribution. The paper suggested that values of a 7% EPOC for steady state work but 14% for interval work were approximately correct values so that’s what I’m going to use.

As I mentioned yesterday, and want to look at in more detail today, although 14% sounds impressively larger than 7%, this can be terribly misleading. 7% of a large number can still be more than 14% of a much smaller number even if the percentage contribution is higher in the second case. And no matter how you cut it, the majority of calories burned come during the workout, not afterwards.… Keep Reading

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A 45-Minute Vigorous Exercise Bout Increases Metabolic Rate for 14 Hours

In recent years, there has been a focus on the calorie burn after training.  Colloquially referred to as the “afterburn effect” and more technically as EPOC (Excess Post-Exercise Oxygen Consumption), a number of popular training approaches have been advocated to try to leverage it for fat loss.  But there is a long held issue regarding the absolute magnitude of EPOC and how much of a contribution it actually makes.  I want to address this issue by examining the following paper.

Knab AM et. al. A 45-Minute Vigorous Exercise Bout Increases Metabolic Rate for 14 Hours.  Med Sci Sports Exerc. 2011 Sep;43(9):1643-8

Background on EPOC

As stated above, EPOC stands for the Excess Post-Exercise Oxygen Consumption and this represents the calories burned after a workout has been completed.   For years EPOC was thought to be related to the “oxygen debt” from exercise, essentially the difference in how much oxygen was needed during exercise and how much was available. … Keep Reading

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Steady State vs. HIIT: Explaining The Disconnect

In this series of articles, I’ve been addressing some issues relating to the debate over steady state and interval training for fat loss.    In the last two posts, hopefully I’ve made the point that a lot of what the pro-interval crowd is resting the benefits of interval training on (namely EPOC, which is the post-exercise calorie burn) is a whole lot of nothing.

With any realistic amount of intervals, not only does the total calorie burn of the workout itself pale compared to longer moderate intensity steady state sessions, the EPOC simply doesn’t amount to anything. Certainly not enough to explain the rather rabid and myopic recommendation of that form of training.

Yet we seem to have something of a real-world problem, there is an apparent disconnect with the physiology that I’ve (so-far) looked at and the results of research (or the real world), many of which are showing greater fat loss with the interval versus steady state exercise mode.… Keep Reading

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Steady State and HIIT

In recent years, there has been quite the over-popularization of the concept of high-intensity interval training (HIIT), along with a rather major backlash against traditional forms of aerobic training, for fat loss. It’s not uncommon to read how low intensity aerobics is useless for fat loss, everybody should just do intervals, regular aerobics makes you lose muscle, etc. I have seen it claimed that aerobics will make you fatter, stress the adrenals, and all manners of fascinating claims.

Nevermind that, over the decades, bodybuilders have gotten into contest shape with (often endless amounts of) cardio, runners, cyclists and swimmers are extremely lean, etc. Somehow, aerobic training has gotten a bad rap.

While I have written about this in a previous article series, I wanted to revisit the topic again since I see the same (usually incorrect) ideas being thrown about.

Where Did this Idea Come From?

I think what happened is that for about 2 decades, aerobic training has been (over) emphasized over all other kinds of activity.… Keep Reading

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Steady State vs. Intervals: Summing Up

In the previous article, I looked at research examining The Metabolic Effects to Short-term High-intensity Interval Training.

Summing up briefly, it showed quite clearly that, at least in relatively untrained individuals, a short-term (2-6 week) program of high-intensity interval training (workouts typically done three times per week) can generate similar adaptations to longer duration training.

In that post, I finished by asking the following questions:

There’s no doubt (and I haven’t intended to suggest otherwise) that high intensity interval training can have benefits. It’s time effective and may induce similar performance adaptations to longer duration traditional cardio. With regards endurance athletes, it’s clear that even short periods of low volume interval training can have rather large benefits for performance.

But with most of the benefits seeming to occur with only a handful of sessions per week (2-3 is the norm) and with benefits appearing to end fairly quickly (3-6 weeks), we might ask what a trainee should do when either

  1. They need to train more frequently than that
  2. They are looking at their training over a period longer than a few weeks.
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Bodyrecomposition Mailbag 1

Training at Age 46

Question: I was just recently turned on to EFT and now stumbled on to you…. My first article was a link from EFT and found it very interesting. While I didn’t understand all of nuances of the language to describe the science behind the nutrition and physiology of Protein and the synthesis of nutrients, all in all, great article. This article led me to your site, blog and newsletter.

Hey, GREAT stuff. I’ve become a nutrition nerd over the past year and am devouring whatever info I can get my hands on…and this led me to a question you may or may not feel hits a large part of your audience. I continue to read a lot about the goals of hypertrophy, strength and power, what routines are best, what diets are best – but one concern continues to nag at me, over and over; while everyone has different goals, what about AGE???… Keep Reading

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The Four Determinants of Metabolic Rate

In the article You Are Not Different, I made reference to the concept of energy balance and it’s time to expand on that concept by looking at the determinants of metabolic rate.

Energy Balance

In the most simplistic form, we can define energy balance as

Energy Balance = Energy In – Energy Out

Energy in is food, since this is the only place that human can absorb energy (calories and joules are both measures of energy). That side of the equation is relatively simple, just add up your total caloric intake. Actually it’s not because the different macronutrients are handled a little bit differently from one another so it’s not simply calories, but that’s another topic for another section. Energy out is the topic of the next several chapters but ultimately represents how many calories you expend in a day.

Long-term changes in energy balance are what ultimately determine what happens to the body.… Keep Reading

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Categories of Weight Training

While many think of weight training simplistically as any activity where weights (or some form of resistance) is being lifted, this is somewhat simplistic.  Rather, it is useful to look at different categories of weight training based on their goals and how they are implemented.

I’d note that while I’m going to discuss each type of weight training as a distinct entity, it’s better to think of them as overlapping zones (some call this the rep continuum).  For example, the low end of what is typically considered the hypertrophy range (perhaps 5 reps) is often considered the top of the maximum strength range.

What Defines the Categories of Weight Training?

Each of the different types of training is usually defined by what are often called acute training variables (acute here refers to the individual set or workout).  There are a number of different variables that coaches and trainers usually use to define training, including repetitions per set, the number of sets, the rest interval between sets and the load (intensity), to name just a few.… Keep Reading

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Endurance Training Methods: Putting it Together

Having completed my examination of the different methods of endurance training in Interval Training Part 2, I want to examine their application.  As with so many different issues in training, how these methods will be specifically used depends entirely on context.   What a full-time elite endurance athlete might do will be different from a more recreational racer and a mixed sport athlete or general public trainee will differ further.

To adequately address application, I need to examine a few more variables. First I’ll summarize the different methods of endurance training that have been discussed.    I also want to examine the idea of both why endurance athletes often focus their energies on building the aerobic engine from the “Bottom up” and how it works in a performance standpoint.

Methods of Endurance Training

First let me summarize all of the different methods of endurance training I’ve discussed.  Since I’m most familiar with cycling volumes, I’ll be using those most of the time. … Keep Reading