What is HIIT training? And why does it work?

What is HIIT training? And why does it work?

You’ve heard the hype. HIIT is here and it is here to stay. It’s a maximum energy, maximum effort, full body workout designed to push you as hard as you can in only a short period of time. But does it work? Is it really all it’s hyped up to be? And last but by no means least, is it the right workout for you?

We’re going to answer those questions in reverse order for a change…


Is it the right workout for me?

If you're strapped for time, HIIT training might just be for you. HIIT stands for High Intensity Interval Training, and it's exactly that. Short bursts of high intensity intervals followed by short breaks.

Intervals can be anywhere from a handful of seconds all the way up to 8 minutes and they’ll have you working at around 80-90% of your maximum heart rate. If you don’t have a heart rate monitor, you can use the RPE scale.

RPE stands for Rate of Perceived Exertion. Working on a scale of 1-10 where 1 is completely resting and 10 is maximum effort the intended duration. By this scale, you’re looking for an 8-9 effort in HIIT workouts. By the end of any interval you should be starting to feel like you wouldn’t be able to carry on at that intensity.

If you’re gasping for air by the end and don’t think you could have physically carried on at that intensity, you’ve probably mastered the HIIT workout and there are a whole host of incredible fitness and strength benefits to be made through this style of workout.

It's time efficient – A HIIT session should last a maximum of 30 minutes. But that’s not to say they can’t be longer depending on your fitness level and the type of workout you are doing.

Although, if you find yourself completing circuit after circuit it might be worth taking a moment to assess your effort level. If you can handle any longer then get ready for a reality check… you might not be working hard enough!

If we are after time well spent, you can achieve an amazing full body workout in just 20 minutes. In fact, multiple studies have shown that a HIIT training session of 20 – 30 minutes 3 times a week burns calories similar to and delivers the training effect similar to that of 5 longer continuous exercise sessions of between 50 and 60 minutes.

It can be done with little to no equipment – Body weight HIIT workouts are just as effective as those with weights and can be extremely hard. One of our favourite types of HIIT is hill sprints. No kit needed there, just pure grit and determination.

It’s not boring – A HIIT workout is a lot more interesting for many people than standard cardio workouts as a typical HIIT routine will consist of multiple moves that constantly change. That means you only need to focus for short bursts at a time before you get a rest. 


Does HIIT live up to the hype?

What HIIT does best is that it combines all the cardiovascular benefits of endurance training with the strength gains of weight training all in under 30 minutes (generally). By doing this we are maximising our time spent exercising (especially if we live very busy lives) and reaping the rewards of fat burning and muscle building. In doing so, HIIT conditions your aerobic and anaerobic systems. The key difference between these energy systems is oxygen availability.

Aerobic exercise is achieved through steady state intervals and workouts characterised by moderate effort and lower heart rates. You should be able to maintain this effort for around an hour if not more.

Your anaerobic system is incredibly effective at producing short bursts of high energy and power. Perfect when you want to achieve maximum effort back to back with short recovery i.e. HIIT workouts! Anaerobic exercise is great for building muscle, improving cardiovascular health and can burn a lot of calories too.

Be careful though, pushing too hard or for too long will eventually catch up with you as you cannot work anaerobically forever

Does HIIT actually work?
HIIT is a versatile training style and you can use multiple variations on exercises, work time and recovery time to keep it ever changing and challenging.

  • It has been shown that HIIT training leads to greater EPOC (excess post-exercise oxygen consumption). Essentially once you finish exercising, your body will continue to burn calories at a much higher rate than normal.
  • HIIT training is great for burning calories. High intensity efforts create muscle fatigue and use a lot of oxygen and energy which in turn burns more calories.

HIIT workouts also recruits more muscle fibres, which means even more calorie burn and also in the 24hrs post-exercise your body is encouraged to build and maintain lean muscle mass.

  • HIIT improves cardiorespiratory health in a much shorter period of time than other continuous forms of exercises. This means your VO2 max (a standard measurement of cardiovascular fitness) increases. VO2 max is a measurement of the maximum amount of oxygen your body can use. This will increase your endurance, even without doing a training session longer than 20 minutes.

Beginner’s Guide to a HIIT Workout:

If you are designing your very own at home or even gym based HIIT workouts. Remember, you’re after short bursts of high intensity intervals followed by short breaks or slower active recovery periods. 

The exercises are generally cardio but it can be anything from sprinting to burpees to kettlebell swings. The more advanced you decide to make your workouts, the more you might turn to weights and equipment to help you up the ante. But that’s not to say that a simple circuit of bodyweight exercises can’t still deliver the training effect you’re after… because they absolutely can!

Whatever movement you decide to do the main focus is to keep the intensity high throughout the work periods. A typical workout protocol is to use a work to rest ratio of 2:1. For example if you complete 40s of high intensity work and 20s recovery time x 5-10 rounds.

Remember to always perform a thorough warm up before your HIIT workout:

40 seconds work / 20 seconds rest

  1. Squat jumps
  2. Press ups
  3. Jumping jacks
  4. Mountain climbers
  5. High knees
    x 4 rounds

Don't forget a cool down!


Give this a workout a go and let us know how you get on by leaving a comment down below! Don’t forget to share this with someone who you know would benefit from reading this. The U Perform family loves sharing ideas and encouraging each other.