HIIT or LISS: Which one is better for weight loss?

The one thing we cannot buy back is time, so naturally we want to be efficient with it to get the best output, even in the gym. If your sole goal is to lose weight through training then you would want to achieve that goal as fast as possible, meaning you would want your workout to be quick and efficient. So which form of cardio is best for this to be done? Is it a 20 minute High Intensity Interval training (HIIT) workout or is it a 60 minute run on the treadmill at a Low Intensity Steady State (LISS)? Most people would think the answer is simple…. HIIT, its quick and you burn more fat right? Well, that’s not always the case, let’s break it down real quick.

LISS

LISS is a cardio workout that calls for 30-60 minutes doing a simple workout at 60% of your maximum heart rate. You have done this your whole life though walking, jogging, bike riding, swimming etc. What happens during LISS cardio is your body burns more fat as a fuel source, this does not mean you are burning more body fat, it just means your body is only using fat as a fuel source rather then using carbohydrates. Imagine you go outside for a run, when you breath in oxygen it combines with the fat already stored in your body to provide energy. But it can only do this at a low speed/intensity, once you start sprinting then you move away from using fat as fuel and you start using carbohydrates as fuel but more on that later. The nice thing about LISS is that you are burning more calories from fat but because it is done at such a low intensity, the total calories burned during the workout is much lower compared to HIIT.

HIIT

HIIT alternates between short burst of maximum effort and long recovery periods where your heart rate ranges between 80-95% of your max HR during the exercise. An example would be to sprint at maximum speed for 10-20 seconds then recover for 2 minutes before doing it all over again. When this happens your body starts using carbohydrates as the main fuel source rather than fats, more people will learn about this and dismiss HIIT because what good is burning carbohydrates going to do for you when you want to be burning fat? Well, that’s not what matters when choosing between the two, because HIIT hits your body so hard, it stimulates your central nervous system (CNS) which results in your body moving into a high recovery mode. It takes a lot of energy to recover from these workouts meaning that your body uses up a lot of calories to fully recover unlike LISS where only the calories from fats are utilized.

After a hard workout like HIIT, your body goes into post exercise oxygen debt (an increase of oxygen intake following strenuous activity), basically that means after a hard workout your body does not have enough oxygen in its system and it must take time and recover until it is back to homeostasis, that takes a lot of energy to achieve this which means more calories burned while you are recovering. What does this mean for fat loss? It means you burn more fat while you’re recovering, in other words even when you’re not exercising, you’re still burning calories! The downfall, unfortunately, is that HIIT workout are unsustainable, one cannot simply perform HIIT workouts everyday without their body eventually crashing.

HIIT vs LISS

Lots of research has been completed between the two and although HIIT is very effective at getting quick fat loss results, it plateaus very fast and you reach a point there are no more incremental benefits. However, LISS is more sustainable and enables one to burn more calories over longer periods without taxing the body.

So, which one is better? Personally, I think this is the wrong question to ask because it’s relative to the individual and how they structure their training. what should be done is instead of separating the two, one should combine the two into their training program. HIIT workouts should replace weight training on specific days and your LISS cardio should be completed either with your weight training day or on an active recovery day. Personally, I do a HIIT workout once a week and LISS cardio 4 times a week.

Here is a cool workout to try if you want to complete a HIIT workout

20 Minute AMRAP:

● 5 Broad Jumps

● 10 Pull Ups

● 15 Push Ups

● 20 Squats

● 25m Bear Crawl

● 100m Run

Repeat until the 20 minutes is up. These can get pretty brutal!