The Great Debate: HIIT vs Steady State Cardio For Fat Loss?

        HIIT vs LISS 

ABSOLUTELY, any form of cardio & energy expenditure will help burn off calories… but there’s a few key factors that we may want to consider when deciding what form of cardio is best when it comes to burning fat in the most efficient way.

Before we get into depth with the fun details on these different forms of cardio, lets touch on what High Intensity Interval Training(HIIT) is compared to Low-Intensity Steady State(LISS). HIIT refers to very intense short bouts of exercise interspersed with low intensity exercise/rest periods. LISS involves any form of exercise for an extended period at a moderate pace, usually at 60%-70% of your max heart rate AKA the “fat burning zone”



Now let’s dig deeper…

First, we would need to consider which energy source your body uses as fuel. Is your body using your fat stores or glycogen(sugars/carbohydrates) stores?

HIIT is an anaerobic form of exercise that relies heavily on glycolytic(carbohydrate) metabolism for fuel.

Steady State cardio is a form of aerobic exercise that relies primarily on fat for fuel, thus leading many “fitness experts” to believe that this form of cardio is optimal if your goal is fat loss.  



However, studies suggest that HIIT is superior for sustained, long-term fat loss. Moreover, HIIT also enhances muscle gain in active individuals, whereas LISS cardio can be detrimental to your hard earned “gains".

How does this make sense? Well LISS cardio(i.e. walking on the treadmill) is used at a steady pace increasing oxygen delivery to your heart and lungs. On the contrary, HIIT works more on your muscles, aiding in more efficient oxygen delivery so your heart doesn’t have to pump as much to make them perform.

Another factor involved when considering your choice of cardio for fat-loss is your resting metabolic rate. HIIT cardio will increase your excess post-exercise oxygen consumption(EPOC). In simpler terms, this refers to your body burning more energy/calories at rest than you normally would.

Research has shown HIIT provides more metabolic adaptations such as:

·      Reduced appetite

·      Improved Blood Lipids

·      Enhanced Vo2 Max Output

·      Better Heart Health

·      & more endocrine activity

Now before you go ahead and ditch your LISS cardio, while it may not show to be as effective in fat-loss as HIIT, I believe it is beneficial to keep a balance between the two. LISS plays a role in situations when you need to burn calories without taxing yourself excessively, which may occur if you over-do HIIT style cardio by stimulating your nervous system from the increase of adrenaline.



Intuitively, one can see why HIIT would be optimal for someone looking to lose fat and live a healthier life. 2-4 HIIT sessions is the sweet spot respectively considering your fitness level, any more than that and you’ll more than likely burn out. Incorparating LISS minimally will also benefit in case of a stall in your fat-loss journey. More importantly, I find it crucial to enjoy your cardio, whether it be HIIT or LISS. Find bliss in the process to a better you!


Written by:  Angelo Minuche 

NASM Certified Personal Trainer