The What & Why of High Intensity Interval Training (HIIT)

Posted on July 09 2018

The What & Why of High Intensity Interval Training (HIIT)

HIIT (high-intensity interval training) is a method of working out where you alternate between periods of all-out intensity and low-intensity recovery.

The concept is simple: push yourself almost as hard as you can, and then try to catch your breath in preparation for the next push. Do this at intervals for 15-20 min, and you'll be smoked.

High Intensity Interval Training has been scientifically proven to burn more fat in a shorter amount of time vs. Low Intensity Steady State cardio (LISS). A study conducted by researchers in Ontario found that individuals lost more fat doing 4 to 6 sets of 30 second sprints OVER 60 MINUTES OF INCLINE WALKING. In other words, 17-27 minutes of HIIT was MORE effective than 60 minutes of traditional cardio.

In addition, HIIT can:

  • increase your metabolic rate for up to 24 hours
  • improve insulin sensitivity in the muscles, which helps your body better absorb and use the food you eat
  • increase your muscles’ ability to burn fat for energy
  • elevate (HGH) growth hormone levels, which aids in fat loss and muscle building
  • spike catecholamine levels, which are chemicals that mobilize fat for burning
  • decrease post-exercise appetite, which helps prevent overeating.


HIIT as a method of fat loss and even muscle development is clearly (scientifically) effective. BUT - what actually serves as a HIIT workout... and how do you get the most out of HIIT? It’s actually very simple.

Start looking into the science behind HIIT, and you’ll find that the level of intensity for HIIT exercise is measured in terms of percentages of VO2 max. That means the maximum rate of oxygen consumption during exercise and is the primary element that helps determine endurance.

Most studies show that participants will reach between 80 and 100% of their VO2 max during high intensity periods of exercise. The best indicators of hitting high levels of VO2 max are labored breathing and tension - about 90% of going as hard as you fucking can. Your goal for the High Intensity bouts during HIIT is to reach this point.

Spend about 15-20 minutes performing intervals at this level of intensity, with short rest periods, and you’re on your way to becoming a lean, mean, HIIT machine.

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