What is HIIT and Why is It So Effective?

What is HIIT and Why is It So Effective?

Written By Robbie Peters

1 Jul, 2022

What is HIIT and Why is It So Effective?

HIIT is an acronym for high intensity interval training. This style of exercise has taken the fitness industry by storm over the past decade. In the past, most fitness professionals believed that long sessions of steady state cardio were the secret to fat loss.

Therefore, they asked people to run or jog for 45 minutes to an hour outside or on the treadmill. The prevailing idea was that ‘more is better’. However, after excessive research and testing, scientists discovered that short, intense sessions of training yielded far better results than longer training sessions.

If you stopped to think about it, you would realize that no animal in the wild runs continuously for an hour. It is always short and extremely fast bursts, followed by rest. The lion that chases its prey explodes into action for less than a minute. If it can’t catch the prey, it stops.

The same applies to any other predator. Man is the only animal that runs marathons and subjects himself to long sessions of cardio and later wonders why his joints are giving out.

You are probably wondering, “What makes HIIT so effective?”


The answer is EPOC. Oh great! Another acronym. EPOC stands for excess post-exercise oxygen consumption.

What this means is that when you engage in a HIIT session, your body experiences an ‘oxygen deficit’. It is akin to taking a huge loan from the bank. It is going to take you a long time to repay that loan.

In the same vein, when you are panting and gasping for air while engaged in a HIIT session, your body will be in fat burning mode for hours after your workout is over. It’s repaying the oxygen deficit.

Here is what most people don’t understand – you don’t burn as many calories DURING a HIIT session as you would if you were to jog for 45 minutes. For example, if you jogged for 45 minutes, you may burn anywhere from 370 to 450 calories, depending on your weight and age.

The same person who does a HIIT session may burn only 180 calories within the 15 minutes of training. However, since his body is in calorie burning mode for 12 to 16 hours after the workout is over, he will burn far more than 450 calories overall.

This is what makes HIIT so powerful. The fat burning benefits of jogging and steady state cardio only last during the workout session and quickly taper off after.

With HIIT, you are a fat burning machine round the clock. This is the reason why people who do HIIT see much faster results.

2. Increases stamina.

HIIT improves your stamina greatly. You would think that the long cardio sessions would do a better job of this… but they do not. HIIT sessions force your body into a state of discomfort.
You are constantly operating at your VO2 max. This will greatly improve your endurance.

3. Helps build lean muscle.

While HIIT will not make you gain as much muscle as weight training that’s focused on hypertrophy, it does help to build lean muscle because of the full body workouts. So, you can burn fat and build some lean muscle.

4. Taps into stubborn fat stores.

HIIT will force the body to burn the stubborn belly fat that it loves clinging on to. The body has no choice but to burn fuel because of its energy needs… and HIIT demands a lot of energy.

To conclude, HIIT is NOT an easy style of training. It is hard, tiring and most people will dread it. That is the way it is. You are going to be in the ‘pain box’ for 8 to 15 minutes, depending on how long the session is. However, once you are done, your body will be burning fat for hours after that. You’ll end up losing more fat, start looking leaner and feeling much better. HIIT is something you should include in your training regimen.

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