HIIT Training: How intense is intense?

HIIT Training, or High Intensity Interval Training, is one of the most common and popular forms of training in today’s modern world. With modern life being so busy, people want quick alternatives for everything, including exercise! The idea of HIIT is that you can fit a high volume of work, sets and reps of movement into a shorter space of time, in theory burning a load of calories in a short time frame. On paper, this sounds wonderful, but it obviously can’t be that easy or everyone would be doing it.

In this article, we are going to address what exactly is intense? How do you measure and scale intensity? And some examples of HIIT training.


What exactly is intensity?

Intensity is defined as the power transferred per unit, this is pretty scientific. But at NRG we believe intensity is related to the RPE scale. The RPE is the related perceived exertion scale, this is ranking 1-10 of how hard certain exercise is. 10 is the hardest imaginable whilst 1 is remedial. When completing HIIT style training, you want to flirt with the upper end of the scale. Depending on how hard you are willing to push yourself, some people should be able to touch 10 on the scale. At NRG we wouldn’t recommend touching 10 on the scale everyday as it can take a long time to recover from, not just our cardiovascular system but our muscular and nervous system can suffer.


How do you measure and scale intensity?

So there are many different ways to scale intensity when training and there is no perfect way of training at intensity, as long as the exercise is challenging your RPE. For example you would pick an exercise, for example a squat. From here you would choose the work period, you have a couple of options here. You could:

  • Train for a time period - body weight squat constantly for 30 seconds

  • Train to a number of reps - squat for 10 reps then rest

  • Train to failure of reps - squat as many times until failure, then rest

  • Train to a high level of resistance - squat 3 times at a heavy weight then rest


The most popular format is time. This way you can put in as many movements and reps as possible into a chosen time period. The more you move, the higher the heart rate is, the higher the breathing rate is, the higher the RPE… The higher the intensity!! People want the feeling of sweating and breathing hard during a workout which you might not get from traditional strength or bodybuilding style training, which is why HIIT is so popular.

So in terms of intensity these are common formats for HIIT:

  • Beginners: 20 seconds of work, 40 seconds of rest for a number of sets

  • Intermediate: 30 seconds of work, 30 seconds of rest for a number of sets

  • Advanced: 40 seconds of work, 20 seconds of rest for a number of sets

For more advanced trainers you want to be working more than you are resting whilst the less experienced trainers should be resting more than they are working.


What Movements can you do for HIIT?

That is the beauty of HIIT training, any movement can be manipulated into high intensity work. As long as the movements are intense it doesn’t matter if you are doing a bicep curl or a deadlift, you will feel benefits from the movement. Below you can see a classic example of a no equipment style hit session:

5 Rounds of:

  • Squats

  • Press Ups

  • Ab Mat Sit Ups

  • Lunges

  • Bear Crawls

So depending on your experience, decide how long you want to do each exercise for. If you are an experienced trainer perform each movement for 40 seconds rest and if you are a beginner then perform the movement for 20 seconds followed by 40 seconds rest! It is that simple.

This is why HIIT is so popular, in 5 rounds of 5 movements you are fitting in 25 sets of exercise into 25 minutes. That is a lot of movements which means a lot of calories burnt in a short period of time! A good personal trainer will know all this already, but it is good to be aware how to set up your own HIIT!


And that concludes this article on HIIT training. We hope we have answered some questions with regards intensity and how to scale a workout! Give the variations a go and let us know how you get on. If you want more amazing content before anyone else, then simply join the NRG mailing list by filling in the form below. You will receive articles on training, rehab and performance alongside getting to know exactly what is going down at NRG. Feel free to comment below or contact us on rob@nrgsportstherapy.com if you have any more questions.