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HIIT Training vs LISS Workout: Which Is Best?

Ah cardio. You either love it or hate it. Some of us were born to burpee while many of us wouldn’t be seen dead breaking a sweat. But there are so many ways you can work cardio into your routine – there’s more to life than the treadmill, y’know?!

HIIT has fast become one of the most popular ways to get sweaty. High intensity interval training doesn’t need to take up your entire day– think 20 minutes of circuit training or some killer hill sprints. It’s perfect for those short on time or for those who are keen to get their dreaded cardio session out of the way as quickly as possible.

LISS, otherwise known as lower intensity steady state exercise, is more suited to those who prefer longer, steadier workouts. A long, brisk walk or an hour of breath stroke down at the local swimming baths, for example.

When it comes to working out, many of us consider what exercise burns the most calories over which we actually enjoy. But, out of HIIT and LISS, which is best? We asked team Grenade® athlete Vinny Russo to settle the score between the two.


"When taking a look at cardio, the real debate is between HIIT vs LISS cardio. HIIT, or High Intensity Interval Training, involves short bursts with high effort, followed by lower effort rest intervals. LISS, or Low Intensity Steady State, involves consistent effort at a steady pace for an allotted amount of time (the heart rate is usually monitored here to identify effort).

Research shows that LISS forces the body to use fat as its main source of fuel for the workout, to where HIIT, due to its intensity, will use glycogen or carbohydrates as its main source of fuel. They both hold true to those statements but when the session is over, the amount of calories being burned is around the same. This statement contradicts the EPOC reasoning for why most people believe that HIIT is more beneficial.

The EPOC (Post Exercise Oxygen Consumption) effect involves the body burning more calories due to an increased oxygen consumption post exercise in the hours following the workout. Compare that to LISS which is said to not have a form of EPOC effect at all. As for research on the effects of EPOC in terms of calories burned, there are multiple studies showing that the effect is not substantial and should not influence one form of cardio over another.

In ‘layman’s terms’, HIIT has very high caloric expenditures followed by very low caloric expenditures, and LISS has a stead state of caloric expenditure. So, at the end of the workout, this would mean they pretty much equal out in terms of calories being burned. So, which one should you go with? This leads to the time and exertion of each.


Now, slow and steady takes a longer time to finish, but is easy to do, and puts minimal stress on the body. HIIT on the other hand, adds a lot of stress to the body, is extremely hard to finish (if done correctly), but takes a shorter time to complete. So, you need to decide which form of cardio will best fit your lifestyle. It literally all depends on what you feel is best for you. If you have the time to do an hour of cardio at a slower pace, and you don’t want to put your body through stress then slow and steady is the path for you. If you are limited on time and like to put yourself through some cardio pain, then HIIT is the path for you.

Personally, I favour HIIT because I need to feel as if I’m working. I need to feel out of breath and I need to feel a burn. It's convenient for me that I can finish a cardio workout in 10 to 20 minutes instead of 40 to 60 minutes. I feel as if the 20 minutes is a lot easier to fit into my schedule than an hour is. HIIT also keeps me interested as I can have fun with it. I will add that I am not married to one form over another as I do a mixture of both depending on the day. If I feel like a long jog is better, I’ll do that or maybe head to the track and do sprints; it all depends on my mood.


When to do your cardio is also a popular question, which has a very easy answer - you do it when you can! In the morning on a fasted stomach has research for and against the claims of burning more body fat. I like to do my cardio in the morning just to get it over with, not for the previously mentioned effect. You may tap into body fat for energy in a fasted state, but if you eat before your cardio, it may provide more fuel to push harder and longer. It does not matter what time of the day you do it, so just do it when it fits your schedule.

With that being said, you also need to understand that cardio should only be a tool used to aid in fat loss, and not a necessity. Your body adapts to stress very quickly, so it will adapt (become better conditioned) to the amount of cardio you stress it with. This will then mean that you will have to add more cardio just to keep the fat loss effects of it. So, use it strategically and sparingly if your goal is fat loss. If you LOVE cardio, you use it as your main form of working out, and are using it for cardiovascular purposes, then have a blast doing what you want with it!"

So, the simple answer is do whichever you like the most! HIIT is best for some, while LISS suits others better. Either way, you’re moving and that can only be a good thing!

For more fitness and training advice, head over to our blog. You can also follow Vinny on Instagram for more tips and inspiration.