HIIT vs LISS (What you need to know)

There has always been a divide between the two main forms of cardio training.

High-intensity training or steady-state cardio.

It's up to you to decide which one is better, for you.

Somehow, it has managed to become this scenario where either one is the supreme ruler and the other one, just plain sucks.

What if I told you that this wasn't actually the case.

  • They are both useful.
  • They both have benefits.

In saying that, one style may be a better fit for you and your goals than the other.

Both pills (and training styles) have the ability to improve your health, fitness and body composition.  So, which do you pick...

Both pills (and training styles) have the ability to improve your health, fitness and body composition. So, which do you pick...

I hope to provide you with enough detail and information so that you can employ the correct style for your goals and achieve long-term fitness success.

What I’d like to do initially, is describe the two training styles and give a brief explanation of what they are. Then, I will dissect their key differences.


High-Intensity Interval Training

A form of training where you alternate between a low-medium intensity effort and high-intensity effort.

This leaves you with big peaks and troughs with regards to your heart-rate. It spikes, then drops and you repeat that cycle for a given number of intervals, or rounds.


low-Intensity Steady-State Cardio

This type of training requires you to remain at a low-moderate level of your maximum heart-rate for a prolonged period of time.

No peaks or troughs. Just a steady heart-rate from start to finish.

Before I get any further, if you are wondering, “Do you even need to do cardio”? You first need to know what your main goal is.

If it is a goal from the list below, I would highly encourage you to find some space in your program for some form of cardio training.

  • Improved body composition (Body shape)
  • Better heart function
  • Easier to pump blood around your body
  • Stress reduction

Now, let’s dig into the two main forms of cardio and what they can do for you.


Low intensity cardio has been a staple in gym programs for years and years. And with good reason.

It works!

LISS is a fairly easy form of exercise that just about everyone can do and get a benefit from.

Whether it be walking, riding a bike or going swimming, you can use this type of training to develop a massive base of fitness.

Below are the two main benefits that I’ve found from incorporating LISS into my training and clients programs.

1) Burn extra calories

The simple act of moving - in any form - will lead you to burn calories at an accelerated rate.

This is good for fat loss!

If you find yourself maintaining your current weight, or not having it come off as fast as you'd like, this should be your bread and butter.

It's easy to do.

You can do it in many forms.

Just pick the one which appeals to you, or you have access to and roll with it.

Here's the catch: It needs to be at least 30mins long.

Steady-state cardio isn't something you have to do at a high, or intense level, which is why I encourage a minimum of 30 minutes.

You get to tap into your fat stores, it won't beat your joints up and is good for your mental health, too.

So take the time to enjoy it!

Medium-Long distance running is a popular choice for low-intensity training.

Medium-Long distance running is a popular choice for low-intensity training.

2) Speed up the recovery process and reduce DOMS

Doing LISS will benefit you in the fact you have lots of blood pumping around your body.

This helps get rid of waste products in the body and also promotes small repeated muscular contractions.

If you're sore from a previous training session, it may feel uncomfortable, initially - but it will go away.

This type of training will also increase your stroke volume.

Stroke volume =  The amount of blood pumped around your body, per beat.

Ideally, you want your body to pump lots of blood per beat, so it doesn't have to do it so frequently.

This means you become fitter and your heart becomes more efficient. Excellent for heart function and health.

It also means that you will recover quicker between sets of weights and any interval training that you do.

As Mike Robertson says, “Use low-intensity work to drive high-intensity sessions!”


This training style is rapidly becoming a popular choice for fitness enthusiasts, but I’d urge some caution before getting caught up in the hype.

HIIT training can be quite detrimental to joint health if you don’t perform it correctly, or if you are simply carrying excess weight.

The sheer amount of impact you place on your joints from jumping, landing (incorrectly) and doing explosive-type movements is a freightening thought for newcomers to the fitness scene.

If you are brand new to fitness, or just want to “ease your way in”, this may not be your best option.

Now I’ve got the disclaimer side of things out of the way, let’s talk about the benefits that HIIT training can have.


This acronym is a fancy way for saying you will burn calories at a faster rate, even AFTER you finish training, as you are trying to regain lost oxygen.

EPOC stands for, Energy Post-exercise Oxygen Consumption.

When you perform HIIT training, your body cannot uptake and utilise enough oxygen to sustain working at such a high intensity, which is why it is performed in bursts, or rounds - so that you can recover and then repeat the process again.

What ends up happening over the course of a training session is that you place more and more demands on your body to get oxygen to the working muscles so you can perform at a high level of your maximum heart-rate.

The oxygen demands at the start of your session are more easily met than at the end of your session, as your body is being more and more depleted of oxygen, thus, creating a big oxygen debt.

And like any debt, it must be repaid.

In your case, it gets paid back in the form of burning calories at a higher rate until your body returns to 'homeostasis', or neutral.

This is where oxygen levels are returned to normal and your body doesn’t have to work so hard to maintain its regular functions.

The key with HIIT training is that the training intensity, or difficulty, MUST be high.

I’m not talking about being slightly out of puff, here. I’m talking about working between 80-100% of your absolute maximum capacity.

You will huff and puff, breathe hard and probably sweat an awful lot, too.

HIIT work isn’t designed, or meant to go for long periods of time. It should be short and intense.

The shorter the duration, the higher the intensity, and vice versa.

This article covers volume and intensity in much more detail.

My recommendation would be to keep HIIT work between 10-20 minutes per workstation and 30 minutes of total work.

If you can do more than that, you didn’t work hard enough, or, you can (and should) push harder next time.

Ahhh, the Concept 2 Rower.   Love/Hate  relationship every time!

Ahhh, the Concept 2 Rower. Love/Hate relationship every time!

2) Greater athleticism

Interval training also has the potential to boost your athleticism and return you to the feeling of when you were young(er) and had the capacity to run, jump and sprint with purpose.

After performing high-intensity work for a decent period of time, you start to develop a mindset of “embracing the suck” and almost look forward to the hard work.

This shift takes time, but when you reach this level, you’ll notice your results improve exponentially!

You might even seek out things which challenge you and start to think more laterally, when it comes to figuring out what to do for training.

Instead of doing the stationary bike, or treadmill, you might decide to do ‘repeat shuttles’, or 'the beep test'.

Or maybe, that’s just me?

Hill sprints, or a 30-minute intense spin class might start look appealing to you!

Appealing in a way of results, not always in terms of satisfaction.

But, therein lies the biggest difference between LISS and HIIT.

Low-intensity sessions require little to no mental stimulation or motivation.

High-intensity sessions can be more demanding on your body, joints and certainly require more input mentally.

Below is a quick checklist to help you find the best fit for your goals.

  • Are you brand new, or want to “ease into exercise”? If yes, LISS
  • Are you overweight, or have any lower body joint issues? If yes, LISS
  • Do you always require inspiration or motivation to train? If yes, LISS
  • Have you been training consistently for a while, or play a sport? If yes, LISS and/or HIIT
  • Have you reached a plateau with weight-loss and want to spark fresh progress? If yes, LISS and/or HIIT
  • Would you like to improve your willpower and mental muscle? If yes, HIIT
  • Do you like a challenge and enjoy pushing yourself physically? If yes, HIIT 
Fulla Strength and Conditioning

Can you do both? Yes.

For the goals of fat loss or muscle-gain, I recommend employing a combination of both forms of cardio.

HIIT training can be done at the end of your weights session, or as a stand-alone session, if you have the time.

The low-intensity work can be done in the form of walking your dog, going for a scenic walk or bike ride on the weekend and even watching a T.V show/movie whilst walking on a treadmill.

Far too often, I see people complicate this process.

Just pick a style of training (HIIT or LISS), a method to perform it (Walk, sprint, cycle, swim, other) and then decide how long to do it for.

You're now ready to rock and roll!

If you have any questions or would like more information about the two training styles, please comment below and I'll get back to you with an answer.

Until next time,

Pick your cardio and get it done.