The Cardio Debate For Fat Loss: High Intensity Versus Low Intensity

Rosie Chee
Written By: Rosie Chee
August 3rd, 2012
Updated: June 13th, 2020
Categories: Articles Fat Loss
57.2K Reads
Find out the five reason why high intensity cardio sessions are far superior and more effective for fat loss than low intensity cardio.

Woman RunningIt is a mistaken belief that long and slow, low intensity cardio is best for fat loss because it utilizes the aerobic system and burns fat during exercise. High intensity cardio is actually far superior and more effective for fat loss than low intensity cardio for several reasons.

This article will briefly discuss the differences in high intensity and low intensity cardio, outlining the reasons why high intensity cardio is more efficient and effective for fat loss.

High Intensity vs. Low Intensity Cardio

Time Efficiency

High intensity cardio requires less time to perform an effective session than low intensity cardio, which makes it a much more convenient mode of cardio for those with limited time in which to train.

Substrates Used

Although high intensity cardio primarily uses carbohydrates for fuel, the higher oxygen deficit post-training causes the body to use fat for energy. High intensity cardio elicits a higher work response from the body than low intensity cardio, thus burning more overall calories throughout the day, even if not during the training session. Training the body to perform at a high intensity will also increase your body’s tolerance for work, and therefore the body will burn fat at a higher level, sparing muscle glycogen.

Because of the higher force of muscle contraction during high intensity cardio, there is a greater rate of GLUT-4 translocation within the muscles, creating a stronger nutrient repartitioning effect, which in turn enables the body more efficient and effective used of substrates.

Oxygen Utilization

High intensity cardio has a higher oxygen deficit than low intensity cardio. Training with a higher oxygen deficit actually increases the body’s maximum oxygen capacity more than low intensity cardio. The higher the body’s maximum oxygen capacity, the more efficient the body is at oxygen transportation, and thus more efficient the body is at burning fat, since fat requires oxygen to be oxidized.


Hormonal Responses

High intensity cardio elicits a similar hormonal response from the body as resistance training does, but without the stress and strain on the body and the nervous system that resistance training has. Higher insulin sensitivity, more growth hormone and IGF-1 release makes the body more effective at burning fat.

Muscle Mass

Burning fewer calories during the training session makes high intensity cardio more muscle sparing and less catabolic than low intensity cardio.

High intensity cardio uses fast oxidative (i.e. Type IIa) and fast glycolytic (i.e. Type IIb) muscle fibres. Muscle hypertrophy occurs primarily through chronic anaerobic, high-intensity exercise. The more muscle mass an individual has, the greater the ability of their body to burn fat.


If you want to lose fat quickly and efficiently, high intensity cardio is the best mode of cardio to incorporate into your training program. Not only does it require less time to complete, but it burns more overall calories throughout the day.

High intensity cardio makes the body more efficient at using oxygen and elicits the same hormonal response as resistance training - without the stress on the body - allowing for the same fat burning ability. High intensity exercise is also muscle sparing, due to the shorter exercise period performed and less calories burned during the session, allowing the body to be a more effective fat burning machine, since more muscle mass means a greater ability for the body to lose fat.


  1. McArdle, W. D., Katch, F. I. & Katch, V. L. (2007). Exercise physiology: Energy, nutrition, and human performance (6th ed.). USA: Lippincott Williams & Wilkins.
  2. Norton, L. (2005). A unique combination of science & experiment-based pre-contest advice. Retrieved 18 August, 2010, from
Posted on: Sun, 09/28/2014 - 13:53

This is the best way I ever lose weight from exercise – obviously diet plays a bigger role but when I do this consistently the pounds come off a lot faster (I tend to go on hiatuses from the gym and diet a lot so I go up in weight more than I'd like). 3 days a week for 30 minutes including 5 minute warmup and 5 minute cooldown. At 5 minutes I crank the level up to as high as I can go for 30 seconds and speed up (let's say level 16). After 30 seconds, I drop the level to 5 or 6 and slow down, and do that for a minute. I repeat this until 24m 30s and then crank it up an even higher level, 17. Then cool down for 5 minutes. I'll do the elliptical for 2 weeks, switch to a stair climber or treadmill for 2, then do a the recumbent bike for 2.

It sucks the first week because your body isn't used to the high intensity, but believe me, you get used to it. No, it doesn't get easier, your body will just welcome the challenge. It's hard to explain. But time flies like you wouldn't believe. The 30 second high intensity run feels longer than it is, but the 60 minute rest set is the fastest minute you'll ever experience! I'm convinced that long steady state cardio exercise is a waste of time, and muscle.

By the way, this is my own method, there's a lot of different ways you can do it. Google "Body for life interval training" and "dr mercola HIIT". I sort of combined their methods to make my own. I know the sources may seem a little sketchy but it still works for me. I lost 10 lbs over the last month and have 10 more to go.

Posted on: Tue, 10/22/2013 - 09:37

A tabata is best form of HIT workout

Posted on: Tue, 08/07/2012 - 09:27

I am a big advocate for HIT I have been in track since I was in middle school so a good 11 years ago. I kept up with it even in college! Sprinting is by far one of the best types of HIT as well as interval training which I love. Being a figure competitor and for anyone who is looking to retain or build muscle and burn fat to stay active and healthy or for other purposes lean it is phenomenal! I like to switch it up so sometimes I'll go through a track training split of doing 4 rounds of 100m dash, 4 rounds 200m and so on and taking about 1-2 min rest per 4 rounds. or I'll run hard for 30 seconds and jog or walk for rest for 30 sec (30sec on/30sec off) or i'll do it for a 1min on 1 min off.. and do that for 4 rounds and take a 4 min rest (jog or walk) and repeat 4 more times usually my HIT takes max 30 min! Hope that helps! i love it cause you basically continue to burn calories for about 48 hours your body is continuously working! definitely tests your endurance (physically and mentally), power, strength and speed!

Neil WIlliams
Posted on: Sun, 08/05/2012 - 05:17

Ok, so i was thinking the other day whilst on the tredmill. When i play rugby, I dont run non stop for 30 minutes its in short bursts. So this appeals to me for 2 reasons.

What is the best way to train on a tredmill for this?


Posted on: Sat, 08/04/2012 - 21:22

So we all know HITT is best fot fat lose but what are the advantages of LITT

Posted on: Sat, 08/04/2012 - 18:50

What are some good examples of high intensity cardio exercises?

Posted on: Sat, 08/04/2012 - 17:46

This girl in the treadmill picture is HOT!!! wish my gym could be like that haha

P.S Mix of both Hiits and Liits target the most fat burning in the body and through ur workout