E.P.O.C. – What is it? What? I can turn my body into a calorie-burning furnace?!

The answer is absolutely. YES.  It’s amazing what research within the fitness industry over the decades have discovered – what works, and what doesn’t.  With time, the fads will fade, and the stuff backed by years of anecdotal and empirical evidence will stick, and it’s these principles that drive the innovation and progress that shapes how the fitness industry evolves.

Consider this for a moment: after a long road trip, what do you think happens to your car’s engine?  Once you’ve reached your destination, your car’s engine gradually cools to its resting temperature.  In a similar fashion, your body cools over a period of time after a workout.  But just any workout?  Yes, and no.

After a bout of exercise at the gym, your body’s metabolism remains elevated such that you continue to burn calories (more than you normally would) going about your day-to-day routine.  This physiological response is known as EPOC, or Excess Post-exercise Oxygen Consumption.

“In plain terms, your body has, through exercise, accumulated a debt of oxygen that is required to bring your body back to its normal, resting level of metabolic function (known as homeostasis).”

This elevated metabolic demand on your body post-exercise largely explains why your body continues to burn calories long after your workout has ended.

Let’s break down the science, and get a better understanding of how this affects our body and why it is so effective when applied to the exercise we participate in.

Metabolism is the set of life-sustaining chemical reactions within the cells of organisms, for the purposes of conversion of nutrients as energy to run cellular processes, and eliminate wastes produced by the body”

TW-WEB-Energy-Metabolism

In layman’s terms, metabolism is the conversion of food nutrients to energy.  Taking it a step further, that energy is known as ATP, or adenosine triphosphate, the fuel your body uses for muscular activity.

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How is ATP produced and how do we utilize it during exercise?

ATP is produced in two ways:

  1. Oxygen using Anaerobic pathways
  2. Oxygen using Aerobic pathways

Once you first start a workout, your body uses anaerobic energy and ATP already stored in the body as fuel.  This is why warming-up is imperative prior to commencing a full-blown workout – it takes the body 5 to 8 minutes to start efficiently using aerobic metabolism to produce the ATP necessary to sustain physical activity.  Once this “steady” state of oxygen consumption is attained, the aerobic energy pathways are able to provide most of the ATP for the workout.  In essence, the body has adapted to the type of exercise you are doing, and is able to provide adequate ATP or energy to fuel that workout.  Your body is smart as it is efficient, but with regard to exercise or calorie-burning, is this a good thing? Perhaps not.

If you’ve heard the term “steady-state cardio” before, this is where it comes from.  Steady-state cardio are aerobic-type activities such as jogging, cycling and walking at a consistent, steady pace.  Because the body has adapted, there is no additional demand for oxygen after the workout is done.  Thus, the additional calorie-burning effect (or the engine cooling down period) post-workout is shorter, or even non-existent.  In order to create that post-workout oxygen demand, your body needs to perform exercise that requires the anaerobic energy pathways to be the primary producer of ATP.

So what are the key things to know about the benefits of the EPOC effect?

  • Exercise that consumes more oxygen burns more calories.

    • The body expends about 5 calories of energy to consume 1 litre of oxygen.  As such, increased consumption of oxygen both during and after a workout can result in greater calories burned.
  • Circuit training and heavy resistance training with short rest intervals require ATP from anaerobic pathways, resulting in a greater EPOC effect.

    • Multi-joint, compound movements and workout circuits that alternate between upper and lower body movements places a greater demand on the ATP generated through anaerobic energy pathways.
  • High Intensity Interval Training (HIIT) is the most effective way to stimulate the EPOC effect.

    • The body produces ATP most efficiently through aerobic metabolism, such as when participating in steady state exercise.  Higher intensity workouts where energy is needed immediately shift the demand of energy production to the anaerobic energy system, which can provide the necessary ATP much more quickly.  This is why we can only sustain high intensity activity for a short period of time – simply because we run out of energy.
  • It is the intensity, rather than duration that impacts the degree to which the EPOC effect is produced.

    • As mentioned above, high intensity exercise creates a demand on the anaerobic production of ATP.  When the body is recovering from your high intensity workout and are in the physical state of EPOC, it will continue to use the aerobic energy system to replace the depleted ATP.
  • Resistance training can provide a greater EPOC effect than steady state exercise.

  • The EPOC effect from HIIT workouts can add 6-15% of the total energy consumption to the workout itself.

“I want to get the EPOC effect in my workouts.  How can I do this?”

As you can see, the effect of EPOC is a great example of the understanding scientists, researchers and fitness professionals have obtained over the human body.  Application of this knowledge has rendered numerous iterations of HIIT-style workouts, some of which can be done from home, a gym facility, or a fitness studio tailored to delivering these types of workouts. HIIT training is no longer a new workout phenomenon, but it continues to be an effective tool if you’re looking to not only transform your body composition but also improve your cardiovascular health overall.

I, myself benefited from a HIIT workout regimen when I wanted to achieve my own physical transformation.  I am forever grateful for having found it when I did, because this was the seed that eventually grew into my changing careers and becoming a personal trainer and fitness enthusiast.

So much so, that I now also work as a group fitness coach for a company that delivers HIIT-based workouts, utilizing real-time heart rate monitoring technology that optimizes that EPOC effect, turning your body into a calorie-burning furnace for hours!

I am incredibly fulfilled and proud to be a coach to people achieving incredible results in their own right.  If you want to find out more, contact me or see what Fit United can do for you!


I hope this post helped you get a better understanding of what EPOC is and the benefits of implementing HIIT workouts in your fitness journey.  Please SHARE this post with a friend who you think might also find it helpful!

In my next post, I’ll talk about some ways you can help your body recover faster from your workouts, now that you’ll be exercising more intensely…right!? 🙂

Until next time!

Yours in fitness,

Kevin

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