Maybe you’ve heard of it, maybe you haven’t, but EPOC may be the key to taking your fat loss and fitness to the next level. EPOC stands for Excess Post Exercise Oxygen Consumption, and it works a little something like this:

You know how, at the end of a long car trip, your car’s engine will stay warm as it gradually cools back to its resting temperature? Your body works in the same way.* After a bout of physical activity, and long after you’ve left the gym, your body’s metabolism will stay elevated and will continue to burn extra calories, even if you are at rest. EPOC, also called oxygen debt, refers to how much oxygen is required to return your body to its natural, resting metabolic rate.

The body uses about 5 calories to consume 1 litre of oxygen, so by increasing the amount of oxygen consumed during and after a workout, we increase the amount of calories burned.  Naturally, for fat loss, we want to keep your metabolism revved up as high as possible for as long as possible. Let’s talk about how to use this knowledge of EPOC to our advantage.

Here’s the key: EPOC is influenced by the intensity, and not the duration of the exercise. Research has shown that HIIT (High Intensity Interval Training) and Resistance Training (or weight training) are the most effective ways of stimulating this effect.

Today, let’s discuss HIIT. HIIT, as its name suggests, involves periods of high intensity work followed by periods of recovery. The intense portion can last anywhere from 5 seconds to 8 minutes long, and is performed at 80% to 95% of an individual’s estimated maximal heart rate.**  The rest periods fall within the same time frame as the high intensity intervals, but are performed at 40% to 50% of an individual’s estimated maximal heart rate. The high and low intensity intervals continue alternating until the desired workout time is reached (typically anywhere from 20 to 60 minutes).

Because of the physical demands of HIIT, the body will require more recovery time than it does for other, lower intensity exercise modalities. If you are brand new to HIIT, we recommend starting with just one HIIT session per week. This can gradually be increased to 2 or 3 sessions per week, but make sure to space them out by a full day or two.

Here is a sample HIIT training schedule:

Week 1: HIIT on Monday, Thursday, Sunday

Week 2: HIIT on Wednesday, Saturday

But what about the fat burning zone?

You might have heard that slow and steady cardio is the best for burning fat. This is a half truth. The energy system that your body uses during lower intensity, steady state exercise does run predominantly on fat. However, the EPOC effect from this type of exercise is quite low. That is to say, once the activity itself is done, the amount of calories that you will burn will be quite minimal, especially when compared to the after burn effect of HIIT.

The most important thing to remember, though, is that the best exercise program is the one you are going to adhere to. If you love getting outside and going for long, scenic runs or hanging out on a stationary bike is appealing to you, then do it! And if the thought of working all out to your physical limit and pushing yourself to your maximal heart rate makes you want to shudder, then don’t do it! An imperfect program that is executed perfectly will always yield better results than a perfect program that isn’t executed at all.

At F.I.T., we make sure to incorporate a little bit of HIIT into our clients' regular programming to help them optimize their fitness and fat loss. We have also recently added some evening HIIT classes on Tuesdays, Wednesdays, and Thursdays from 7pm-8pm. For more information on our personal training services or our HIIT classes, contact or call us at 306-979-0151.



*This awesome metaphor courtesy of Pete McCall, MS, CSCS

** Maximal heart rate is the maximum number of times your heart will beat in a minute. It is estimated to be equal to 220 – your age. So, for a 30 year old individual, maximal heart rate would be estimated at 220-30 = 190 beats per minute.

Gonzalez, P; Lizee, T; Gehring, L; Charter, M; and Witzke, FACSM, K (2016) "HEART RATE AND EXCESS POST-EXERCISE OXYGEN CONSUMPTION OF WHOLE-BODY HIGH INTENSITY INTERVAL TRAINING VS. MODERATE-INTENSITY EXERCISE," International Journal of Exercise Science: Conference Proceedings: Vol. 8 : Iss. 4 , Article 37. 
Available at: