High Intensity Interval Training (HIIT) vs Low Intensity Steady-State (LISS) for Fat Loss

Cardio comes in many forms. The two most common types are low-intensity steady-state (LISS), and high-intensity interval training (HIIT). There are other forms, but we’ll leave them for another article. There is an ongoing debate about which is better for fat loss. The answer, as it always is, it depends! Cardio is a tool for us to utilise to achieve our desired results.

In the context of this article, fat loss. Each individual will require a slightly different approach to achieve their fat loss goals. The hierarchy that I recommend is prioritising resistance training over any forms of cardio. Notice how I didn’t say “only” do resistance training. There are benefits of doing cardio; however, in the grand scheme of things resistance training should be at the top of the list. Let’s assume you already have a resistance training plan, and you want to add some form of cardio to complement that. Below I am going to be giving a brief explanation of each modality and give you the guidelines I use with my clients to determine which is best for you to use depending on your situation. Alright, Let’s get into it!

What is Cardio?

For simplicity’s sake, we’ll define cardio as any movement that increases our heart rate from our baseline levels. The definition is an oversimplification. To accurately describe cardio, we need to go into a lot of things. I don’t want to get into these things because, as the general population, not training for particular sports or training for sports specific reasons, it’s not relevant. The increase in our heart rate from baseline can be through exercise equipment such as treadmills, elliptical trainers, stationary bikes, or bodyweight movements done in a circuit or done on its’ own.

From here, we will break it down further to low-intensity steady state (LISS), and high-intensity interval training (HIIT). While researching this article, the term moderate-intensity continuous training (MICT) kept coming up. We will treat LISS and MICT the same in this article.

Low-intensity steady-state

As the name suggests, this type of cardio is low intensity. Think leisurely walk, either at your average pace or a little quicker, a bike ride, swimming, or any other activities where you are not overly straining yourself. A simple way to determine if you’re at the right intensity level is if you can perform the exercise and still hold a conversation with relative ease.

I typically recommend individuals to perform LISS for at least 20-minutes on the low end, and up to one hour or more, on the high end. Depending on the time they have.

Benefits

LISS is a good starting point for individuals who have not done any physical activity for a long time. This is because it is simple to do. You hop on a treadmill or a bike and press go.

Steady-state cardio is an excellent fat loss tool. Fatty acids in fat cells need adequate oxygen to metabolise and be used for fat loss. I can go deeper into the science, which is quite impressive; however, this is not what the article is about, maybe another article.

So besides fat loss, another benefit of LISS is that it is a low impact on our joints, which means less interference with our resistance training regime. Remember, the hierarchy, resistance training is at the top.

Drawback

The biggest drawback with LISS is, as the name suggests, its slow and steady. You need to be doing it for a long time to get the best results from it. The duration can be anywhere from 30 minutes on the low end and up to 90-120 minutes on the high end. A lot of people just don’t have that much time.

High-intensity interval training

This type of cardio is usually represented by alternating between a low-intensity period (think a slow walk), and a high-intensity period (all-out sprint like a dinosaur is chasing you). For the workout to be genuinely HIIT in nature, the high-intensity period should only last between 5-20s, maybe even 30s for advanced individuals. Rest periods vary depending on the exercises being done.

I would prescribe the remaining minute of the high-intensity period as rest. For example, perform 5s high intensity followed by 55s of low intensity, 30s high followed by 30s low. This rule is not set in stone and will change depending on the individual, their training level, and their goal. You need to have adequate rest in-between each round to ensure you can perform the exercise safely and get the most out of the session.

One more point I want to make is that unless you are trained to sprint, then using sprinting/running as a form of HIIT is a bad idea. The risk of injury is extremely high. I recommend doing HIIT on stationary bikes or ellipticals, mainly for safety. Bikes and ellipticals machines are more comfortable with increasing the intensity in that equipment, and there’s no steep learning curve to be able to do it.

Benefits

The most significant benefit of HIIT is that the time it takes for you to do is not very long. HIIT workouts can last anywhere from under 10 minutes to around 30 minutes on the high end. Some of you are probably thinking, “I attended a 1-hour HIIT class before, and it was okay”. Sorry to burst your bubble, but if you can do an hour of HIIT, you are most likely not doing it right, sorry, as the name suggests its high intensity.

Drawbacks

As I alluded to earlier, the biggest drawback for HIIT is the high risk of injury, if not done correctly. A second reason is that most people don’t push themselves enough for the workout to be known as a HIIT workout. The risk for overuse is also extremely high with HIIT workouts- many people want to do it every day!

Now what?

You’re probably thinking, “great, I’ve got some explanation of the different modalities, but I still don’t know which one is best for me?” Don’t worry, Bryan is here to help. To help us in deciding which one to go with, I’m going to be referring to some research articles to back my point.

In a meta-analysis conducted by Li Qiang et al. (2019), they analysed 22 articles regarding whether HIIT or moderate-intensity continuous training (MICT a sub-set of LISS) was more effective for fat loss. They concluded that there were no significant differences between HIIT and MICT in reducing body fat %, Body mass index (BMI), and weight.

Martin et al. (2016) conducted a study where participants were divided into a MICT group and a HIIT group. Participants of the study were given an isocaloric diet (a diet that evenly distributes the three macronutrients of protein, fats, and carbs). They concluded that if the individual is consuming the same calories, MICT and HIIT provided similar results in terms of fat loss.

Zhang et al. (2017) divided 52 female university students into three categories: HIIT (15), moderate-intensity continuous training (MICT) (15), and none training group (13). The study recorded calorie intake, but it was self-reported, so it isn’t reliable. The study set up involved both MICT and HIIT group to continue performing their activity until they reached 300 calories burnt. Both groups used a cycle ergometer as their primary exercise tool. To save you the trouble, the conclusion of the study found no significant differences between the MICT group and HIIT group when it came to visceral fat reduction. Again, if you want to read it for your peace of mind, the article will be referenced and linked below, along with the others I used here.

The conclusion of both studies is unanimous; it does not matter if it is LISS or HIIT; there are no significant differences between cardio form when it comes to fat loss if calories aren’t restricted. We need to be burning more than we consume to lose body fat.

Summary

So which one should you do? Whichever you prefer! As I mentioned above, the two studies, plus the meta-analysis, provided a similar conclusion; that HIIT and LISS (MICT) provided an identical amount of fat loss!

What I would recommend is you first need to be in a calorie deficit to ensure you can burn fat. Secondly, have a resistance training program and thirdly cardio. In that precise order of importance. Which cardio? Choose one that you enjoy doing. If you enjoy long walks, earphones on listening to a podcast, walk if you need to feel like you are dying to have a good workout, do HIIT. Whichever you prefer to do, make sure it complements your program, not take away from it.

Any questions, feel free to comment or DM me.

Peace!

Reference List

LiQiang, S., Jin Mei, F., ShunLi, S., GuangGao, Z., Wei, C., ChuanChuan, D., & Minghui, Q. (2019). Effects of HIIT and MICT on cardiovascular risk factors in adults with overweight and/or obesity: A meta-analysis, Journal of Plos One, 14 (1). doi: 10.1371/journal.pone.0210644

Martins, C., Kazakova, I., Ludviksen, M., Mehus, I., Wisloff, U., Kulseng, B., Morgan, L., & King, N. (2015). High-Intensity Interval Training and Isocaloric Moderate-Intensity Continous Training Result in Similar Improvement in Body Composition and Fitness in Obese Individuals, International Journal of Sports Nutrition and Exercise Metabolism, 26 (3). DOI:10.1123/ijsnem.2015-0078

Zhang, H., Tong, T.K., Qiu, W., Zhang, X., Zhou, S., Liu, Y, & He, Y. (2017). Comparable Effects of High-Intensity Interval Training and Prolonged Continuous Exercise Training on Abdominal Visceral Fat Reduction in Obese Young Women, Journal of Diabetes Research, 9. https://doi.org/10.1155/2017/5071740