Cardio: LISS, HIIT or None?

Everyone makes mistakes on their fitness journey. Everyone grows, everyone learns. In the past I demonised cardio. I remember years ago I would state that “cardio is hardio” and proudly boast about never touching the treadmill. In the online fitness community, at least the one I was a part of, cardio wasn’t cool. And I guess at that time I didn’t know any better. I didn’t have the drive to try and educate myself, to formulate my own opinions. Instead, I followed what everyone else said and took it as gospel.

As time has passed, I have become more open to cardio, and now I bloody love it. LOVE. IT. Which feels crazy to say considering how much I hated it in the past. Back then, I was under the impression that cardio just meant sitting on a cross trainer for 40 minutes. I had no idea how fun, exciting and challenging it could be.

A common question I get asked is whether I do LISS or HIIT cardio, and which one I recommend. This is a pretty tough question because it is completely personal to every single individual. Ultimately I can’t tell you which form of cardio to do, but I can give you some information on the two main types to facilitate you to make your own educated decisions.


HIIT stands for high intensity interval training and it is all the rage right now. It involves short bursts of high intensity exercise, followed by a rest period, and then another short burst of high intensity exercise, and so on. This comes in various different forms from treadmill sprints, to circuit training and spin classes. The intervals can vary from tabata – which is 20 seconds work, 10 seconds rest – through to longer intervals of 20 seconds work, 40 seconds rest. The possibilities are endless.

The Benefits

HIIT is convenient. You can complete a HIIT workout in anything from 5-15 minutes and many HIIT workouts can be completed without using any equipment at all, just your bodyweight. This means it is perfect for travelling or when you’re short on time. I would recommend HIIT for those people who struggle to fit in workouts or don’t have gym membership as they can be easily squeezed into short time periods at home or outdoors.

The Drawbacks

HIIT is hardcore. It takes a serious toll on your body. Through getting yourself to complete high intensity exercises such as sprinting and jumping, you are pushing your body and your central nervous system to its absolute limits. As a result, you can easily get cause wear and tear, or even develop serious injuries. When performing HIIT workouts, please ensure that you are working within your safe limits and you are not sacrificing form for the sake of intensity. I certainly don’t recommend doing HIIT every single day as this will make it hard for your body to recover, repair and grow stronger.


LISS stands for low intensity steady state training. It involves longer periods of lower intensity exercise which stays at a consistent pace. This can come in many forms such as swimming, running and cycling. LISS activities are hugely varied and can range from hiking all the way through to marathons.

The Benefits

One of the main benefits of LISS is that in many forms, it is less taxing on the body than HIIT (unless you’re running marathons every day!). By taking out the high intensity element of cardio, you are less likely to injure your body and cause serious damage.

Another key benefit, for me at least, is that LISS can often allow people to have time to think. By going out for a run, it gives you valuable head space which you can use to reflect on your day, think ahead to the future, or just focus on being in the present. It can enhance mental clarity and help you to destress.

The Drawbacks 

The main drawback of LISS training is the time demands. LISS workouts often last longer than 30 minutes, and can even fill an hour or more of your time. If you’re someone who is super busy it can be a challenge to give so much time to your training.

LISS is less intense than HIIT, but it does also carry (an albeit lower) risk of injury. This is especially true with training such as running where you are putting a lot of pressure through your joints. It is important to ensure that you are using good form and supporting yourself with the right equipment, such as high quality running trainers with personalised insoles.

All In All

I have given you the basic tools and information you need to make a decision about what form of cardio you want to incorporate into your fitness routine. Something to bear in mind is that it isn’t black and white. You don’t have to choose one or the other. HIIT and LISS both have benefits and drawbacks, and its perfectly ok to enjoy a hybrid routine which incorporate both of them. I personally enjoy HIIT classes as well as an occasional run. The one thing that I do ensure is that I care for my body and try to avoid injury at all costs, through warming up and cooling down appropriately, and dedicating time to stretching, foam rolling and trigger point release.

Please, learn from my mistakes. Don’t shun cardio. It is extremely beneficial for your overall health and I strongly encourage incorporating it into your routine in some form. Don’t think that it isn’t for you if you don’t like running. Cardio comes in many different forms. There is bound to be something you enjoy. Whether its dance classes or boxing. Mix it up and find what works for you.

Happy sweating,

Zanna xx

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