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Which is better - HIIT or LISS (low intensity steady state training)?

Now that we understand what HIIT is, it’s time to address the one question that I get asked most frequently….

Which is better – HIIT or LISS (low intensity steady state training)?

I am of two minds when it comes to cardio training. As a former professional triathlete, I have utilised both high and low intensity training and have achieved great results with each. Hopefully I can help you see the pros and cons of both types of cardio training so that you can decide for yourself which form best suits you.


Our bodies are very adaptive. When we spend long periods of time performing LISS, our metabolism adjusts to the low intensity. This leads to a calorie burn that only lasts as long as the exercise. Unlike HIIT that has close to a10-14 hour energy expenditure long after the exercise is over, LISS fundamentally trades calories in and calories out. This can easily be replicated with the same effect and in far less time by cutting the same amount of calories through diet.

(1) A study conducted by Wilson et al. from the University of Tampa, FL, shows when you add in LISS you get a temporary boost in weight loss. Subjects lost a couple of pounds the first week and after that they lost nothing. This happened because their metabolism completely adjusted to that and that became their new set point to what they had to do just to maintain. LISS with a low calorie diet is terrible for fat loss and could cause muscle loss. During a low calorie diet, LISS cardio is more catabolic (muscle wasting) towards muscle as opposed to HIIT cardio being much more muscle sparing.

LISS cardio is more catabolic (muscle wasting) with low calorie diets. Most low calorie diets have low carb ratios in comparison to protein and fat. As we train longer and longer with LISS, glycogen (stored carb in muscle) runs out and the body quickly seeks out a new energy source…. PROTEIN. Once it selects protein as the new fuel source, muscle wasting or catabolism becomes more evident.

(2) In the same study by Wilson et al. it showed:

LISS caused more muscle loss than HIIT.

HIIT caused more muscle retention because when doing LISS you’re not activating muscles the same way as if you were lifting weights.

HIIT is another way to overload the muscle.

• A sprinter’s body composition to marathon runners, more muscle mass.

• High intensity work activates muscle fibers and therefore is a primer for growth.

LISS unfortunately can’t stimulate muscle fibers the same way.


Now that I have shown you the advantages of HIIT when compared to LISS with regards to muscle retention and fat loss, you may think that LISS is completely useless and unnecessary. HOWEVERLISS does have its good points.

• Performing HIIT 5-6 days a week may have a negative impact on weight training and interfere with growth.

LISS is the only option for those with certain orthopaedic, cardiac, and even psychological issues.

HIIT could be dangerous if not used correctly and could lead to injury.


Cardio type selection ultimately is a personal choice. It comes down to which one you will honestly work your hardest at. Both HIIT and LISS require 110% dedication and effort.

HIIT is:

• Quicker
• More effective for fat loss
• Creates metabolic change
• Aids in muscle retention
NOT everyone can do HIIT

LISS is:

• Safer
• Takes twice as long to accomplish similar things as HIIT
• Moderately effective on fat loss

Hopefully this will shed some light as to how to select your cardio training type that is most appropriate for you and your needs. Train hard and leave nothing left in the tank!


1,2) Wilson, et al. Concurrent Training: A Meta Analysis Examining Interference of Aerobic and Resistance Exercise. University of Tampa, FL. J Strength Conditioning.

Former elite athlete, certified massage therapist and KX fitness trainer, Pete’s training style to focuses on body composition and lifestyle change. Utilizing qualities of combined training techniques coupled with alternative disciplines such as Mixed Martial Arts & Strongman, Pete delivers effective and rewarding fitness programs that produce the desired results for all clients.
• Certified Fitness Trainer
• Certified Therapeutic Massage Therapist
• Focus on Intense Cardio-conditioning at HIIT

Conditioning, Cardio, Hiit

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