EPOC | Afterburn – Rapid Fat Loss

Optimising your workout by utilising EPOC

If you are serious about getting fit and building muscle – do it the smart way and implement a little science. EPOC (excess post-exercise oxygen consumption) otherwise known as “Afterburn”.

Do you know your potential for calories burnt in one exercise session? It might surprise you to know that by using EPOC training – you will find your body burns additional calories even after you are done with your workout.

What is epoc?

EPOC (Excess Postexercise Oxygen Consumption) is the additional calories your body burns after an exercise session is completed. The process of getting the body back to the state before the training began takes a variety of processes related to recovery.

  • Increasing the amount of muscle glycogen in the muscle
  • Restoration of blood lactate levels.
  • Lowering the heart rate and body temperature

Post Exercise Oxygen Debt

Since the early 1920’s scientists have hypothesised that certain types of physical activity will cause an ‘oxygen debt’ post-exercise. This ‘oxygen debt’ describes the process the body goes through to return to homoeostasis after exercise. Hill and Lupton first hypothesised the idea of oxygen debt in 1922 and since then scientists have developed our understanding and knowledge of how our body reacts to and recovers from exercise.

Through the utilisation of EPOC principles, it is possible to optimise your workout and your personal fitness. First, you need to understand what EPOC is and why it occurs.

After exercising your body does not go straight back to a resting state. Rather, several physiological processes cause your body to continue working at an elevated rate. Returning your breathing and heart rate to a normal/resting state takes copious amounts of energy.During exercise, there is a cascade of hormones that take place. The process of restoring your body to hormonal homoeostasis also requires energy.

A significant proportion of calories expended post-exercise is due to your body trying desperately to replenish the oxygen in your blood. Replenishing your  ATP, creatine and muscle glycogen. Returning your core temperature to normal. Removal of lactate.

However, not all exercise affect the factors above to the same degree, this is where the application of EPOC principle becomes a useful tool in weight management and overall fitness.A recent study highlights this fact;[1]

The purpose of this study was to compare the effect of both exercise mode and intensity on EPOC while controlling for caloric expenditure and duration.”

What the authors of this study found:

“Total energy expenditure, the rate of energy expenditure, and duration did not differ among trials (p>.05). Respiratory exchange ratio was greater during the RT (resistance training) trial than the SS (steady state, aerobic exercise) trial (p < .05). At 12 hr postexercise, resting metabolic rate (RMR) was higher after the RT trial (4.7 ± 0.67 mL/kg/min) and IT (high intensity interval training” trial (4.6 ± 0.62 mL/kg/min) compared with their respective baseline measurements (p < .008) and the SS trial (4.3 ± 0.58 mL/kg/min; p < .008). At 21 hr postexercise, RMR was higher after the RT trial (3.7 ± 0.51 mL/kg/min) and IT trial (3.5 ± 0.39 mL/kg/min) compared with the SS trial (3.2 ± 0.38 mL/kg/min; p < .008). The SS trial did not influence RMR at either 12 hr or 21 hr postexercise.”

The results show that individuals using weights to train (resistance training) and individuals that did high-intensity training incurred far greater rates of EPOC than the individuals doing steady state aerobic training. Steady state aerobic training refers to exercises in which you maintain the same heart rate/motion for a continuous period. i.e.,) running at a consistent speed on a treadmill.

Another study[2] notes that “An increased rate of triglyceride/fatty acid cycling and a shift from carbohydrate to fat as the substrate source are of importance for the prolonged EPOC component after exhaustive aerobic exercise.” This means that your body continues burning calories after exercise. The more intense the exercise, the more calories will be burnt post-workout. The more intense the workout, the more these calories will be compromised of fat rather than carbohydrates. “The relationship between exercise duration and EPOC magnitude appears to be more linear, especially at higher intensities”.

The conclusions we can draw from these studies are that EPOC has a significant effect on weight management and by utilising exercises that cause a large EPOC response, you can maximise your fat loss.