HIIT Training: The Benefits, How it works & Why you should do it

High Intensity Interval Training (HIIT) is all the rage, but why?  It’s called EPOC, Excess Post Exercise Consumption, a physiological effect that means once your workout is finished your body continues to burn calories as it tries to restore oxygen to the body to reach resting state, or homeostasis.  Exercise that places a greater demand on the anaerobic energy pathways (thats exercise that is short sharp bursts) increase the need for oxygen after the workout, thereby enhancing the EPOC effect.

Here are 7 things about EPOC and how it can help you achieve your fitness goals:  

  1. Oxygen is used for the following things 
    – Resynthesis of muscle glycogen from lactate
    – Restore oxygen levels in venous blood, skeletal muscle blood and myoglobin
    – Work with protein for the repair of muscle tissue damaged tissue during the workout
    – Restore body temperature to resting levels
    – Production of ATP to replace the ATP used during the workout

  2. Exercise that consumes more oxygen, burns more calories.  Therefore, increasing the amount of oxygen consumed both during and after a workout, can increase the  amount of total calories burned.
  3. Circuit training and heavy resistance training with short rest intervals require ATP from anaerobic pathways, which lead to a significant EPOC effect.
  4. HIIT is the most effective way to stimulate the EPOC effect.
  5. EPOC is influenced by the intensity, NOT THE DURATION! Go as hard as you think you can, then a little harder!
  6. Research has shown that resistance training can provide a great EPOC effect than running at steady state.
  7. EPOC effect from HIIT can add 6-15 % energy expenditure. EPOC happens AFTER your exercise session, so that’s while you are going about your daily business, just burning extra energy.

HIIT training is HARD.  Not everyone is willing or able to take themselves to the intensity levels required to get the benefits of EPOC.  If you are using HIIT training to achieve your fitness goals, try to limit yourself to no more than three strenuous workouts per week so you can recover in between sessions.  


Bersheim, E. and Bahr, R. (2003). Effect of exercise intensity, duration and mode on post-exercise oxygen consumption. ​Sports Medicine, 33, 14, 1037-1060 LaForgia, J., Withers, R. and Gore, C. (2006). Effects of exercise intensity and duration on the excess post-exercise oxygen consumption. ​Journal of Sport Sciences, 24, 12, 1247-1264.