Epic EPOC Effect


Epic EPOC Effect

Afterburner has been dubbed one of the best new fitness classes to try in 2017 by Harper’s Bazaar. We chat to Lead Trainer Luke Barnsley to find out why everyone’s raving about it (the clue is in the name).


Afterburner is a class that will leave you burning fat for hours. How does it work?

It’s all to do with EPOC, or excess post-exercise oxygen consumption.

What is that exactly?

Your body uses oxygen in order to create energy. That’s why it’s so important to us. When we exercise we use more energy than when at rest. Therefore our breathing rate increases. Our body increases our oxygen intake to supply our body with more energy for the increased work. Working in this way is anaerobic exercise, meaning ‘without oxygen’.

Ok, I’m with you so far, but that still doesn’t explain what EPOC is.

If you embark on vigorous exercise, or high intensity exercise (like an Afterburner class for example) you place a massive energy demand on your body. A demand that’s higher than the amount of oxygen that can be absorbed through the respiratory system at that time. If you continue working in this way for a prolonged period, then your body must create energy without oxygen. Or anaerobically. Unfortunately for us, generating energy this way produces waste products such as lactic acid – which is what creates the ‘burn’ in muscles during high intensity exercise and the body has to work harder to remove these waste products. If your body works in this way it builds up what is called an ‘oxygen debt’.

So an oxygen debt is what counts?

Essentially yes. An oxygen debt is what we refer to when we talk about EPOC. You train really hard, force your body to work anaerobically and an oxygen debt is created. Then afterwards, like many debts, it has to be paid off. In the time after the session your body consumes more oxygen than it would normally. This is because it is busy neutralising all those waste products that were created when you worked without oxygen. An increased breathing rate means an increased metabolism, meaning your are burning more fat than normal during this time.

So if I generate EPOC my body takes in more oxygen when at rest, and this is helping me burn fat?

Exactly. EPOC causes a massive increase in metabolism, or greater fuel demand, which when combined with a calorie deficit can cause a higher rate of fat loss.

How does Afterburner generate an oxygen debt?

Afterburner is a hardcore functional circuit that utilises the toughest athletic-based movements, movements that require massive amounts of energy. The class runs at an extremely high tempo, with very little rest. You put challenging movements at a high tempo, with little rest and you force your body into an anaerobic environment. Once there, the class keeps you in that environment for prolonged periods. Your body has no choice but to accrue a massive oxygen debt. You become a fat burning machine.

How long does the EPOC effect last?

It can last for as much as 24 hours after the class. Your breathing rate will still be affected, meaning your metabolism is up. If nutrition is stable, the body will use it’s fat stores to provide the requisite energy.

Luke is the Third Space Lead Trainer for Afterburner with over 10 years of experience and teaches the class across all four clubs. Luke regularly writes for Men’s Health and Women’s Health and has been featured in The Evening Standard.

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