The Death Of Low Intensity Cardio | Gymtalk

The Death of Low Intensity Cardio

We’ve all been there at some point in our lives…

Cutting those last few pounds of fat ready for the beach; preaching ‘no carbs before Marbs’ like some kind of religious fanatic; walking on the treadmill for the duration of an entire Jeremy Kyle show in a vain attempt to get as shredded as possible.

What if I told you (much to the chagrin of fellow Gymtalk writer Henry Croft with his marathons and silly phases of running) that hours of steady state cardio are no more beneficial (and potentially worse) for fat loss and fitness, and you should bin it off for the rest of your life?

Well before you tell me to ‘do one’, let me drop some knowledge bombs on you to try and change your mind.

Homer chair treadmill gif

The science

Let’s start with this:

Burgomaster et al at McMaster University performed a study where individuals aged 20-22 performed either high-intensity, low-volume sprint-interval training or more traditional, high-volume, endurance training.

At the beginning and end of the study the subjects were tested to see how long it would take them to complete an 18.6 mile cycle ride on a stationary bike.

Both groups would exercise three times a week for two weeks.

The first group performed 3-5 intervals of 30 seconds of high intensity work followed by four minutes of rest while the other group performed 90 to 120 minutes of steady state cycling.

I know which group I’d rather be in!

One group exercised a whopping 97% more than the other – so you’d expect them to perform better right?


When both groups were tested at the end of the experiment they performed exactly the same.

The low intensity group wasted all that time for no benefit.

So even if you ditched the long slogs on the ‘mill you’d be fitter even if you were no slimmer.

But there is more…

Feel the burn

When you perform steady state cardio you solely operate on the aerobic metabolic pathway.

It’s fairly efficient and can potentially go on forever.

Every time one molecule of glucose heads down this pathway it yields 36 molecules of ATP, the body’s energy currency.

However if you actually work hard and enter the anaerobic energy pathway, you activate a much faster system that will quickly build up pyruvate, the substance that is taken into the mitochondria to be used in the aerobic pathway, outside the mitochondria.

This pyruvate stacks up and is turned into that old bastard lactic acid by another enzyme.

By pushing the build-up of pyruvate to a rate that is quicker than the aerobic cycle it causes the aerobic system to function as quickly as it possibly can.

This is chemically mimicking the effects to traditional ‘cardio’.

As you recover from high-intensity training the lactate is reprocessed back to pyruvate and metabolised aerobically anyway.

This is even more stimulation of the aerobic system than you would get from low intensity work.

So you’re getting a double (well one and half) whammy of training doing HIIT.

feel the burn family guy meme

But what about fat loss?

During ‘emergency situations’, evolutionarily speaking, or severe muscular exertion, the hormones released stimulate the mobilisation of fats which will release, down the line, another 35 molecules of ATP.

An intermediate in this process is also shuttled to the liver and converted to glucose which is metabolised again yielding a ridiculous 96 units of ATP.

This process is only activated by High Intensity Training, which should really bust the myth that High Intensity Training does not ‘burn fat’.

Could low intensity cardio make ‘fat burning’ even harder?

So during high intensity exercise you should use up the majority of your muscle glycogen.

Now when you re-feed, all those carbs you eat will go directly to the muscle and be stored for future use.

This glycogen emptying significantly increases your cells insulin sensitivity which is a vital mechanism you need when trying to pack on muscle again.

Forget the ‘one hour post workout window’.

With good high intensity training you can make a replenishing period last for as long as several days.

So now imagine you’ve just done a treadmill trek and used almost none of you muscle glycogen and you then have something to eat.

Any carbs or fats you have to eat are not needed to be stored as glycogen so they are destined for one thing.

They can only be stored as fat.

Full glycogen stores plus elevated levels of carbohydrate in the body can only spell disaster for your fat loss.

Not only that but the type of fat created from this scenario is ‘bad fat’.

Along the line it is turned into artery clogging LDL cholesterol, a marker for a whole host of cardiac diseases.

So by doing stead state cardio you might be doing yourself no favours at all!

Cardio ruins gains brah!

Often quoted as broscience, but it does actually have an element of truth to it.

cardio step brothers meme

Over long periods of exercise your energy levels will drop to the point that muscle tissue will be broken down and used as energy reserves.

So it really will causes you to lose your hard earned muscle.

When you do high intensity exercise the actual work time is so small that your body will not need to take this emergency action to keep you ticking over.

“Shut up nerd!”

Okay, so that’s probably enough science even for Richard off of Pointless.

So how can you put all this to good use?

First of all ditch that LISS cardio or whatever you want to call it for good, and, instead, every time you want to burn of some flab, try this:

Get on the cycle.

This has been shown to be the most muscle sparing piece of cardio equipment.

Perform a five minute warm up at a relatively easy resistance and speed.

Now, here comes the fun part:

At the top of a minute build up your pedal speed for 10 seconds, after that turn the resistance up to full (yes, all the way!) and pedal as hard as you can for another 30 seconds.

Now relax, for three whole minutes.

That’s right, turn that resistance down and barely pedal at all to fully recover.

Repeat all this 4-6 times and you’re done.

Better than a 60 minute stroll on the treadmill I’m sure you’ll agree!

For added motivation, take heed of Dwight’s words:

Just one thing…

There are a few things to consider when performing High Intensity exercise.

1) Warm up properly

I cannot stress how important this is.

If you are going all out with cold muscles you are almost certainly going to pull a muscle.

2) All-out means all-out

As my old swimming coach would say, “You need to put in a balls-out performance here”.

High intensity does not mean ‘slightly harder than resting’.

It means you have to put in 100% or this will not work.

You get three whole minutes of rest so don’t be scared to give it everything you’ve got.

At the end of the interval you should just about be able to hold yourself upright and that’s about it.


3) Your muscles, your heart, and your cells don’t know what exercise they are really doing

They just know they’re working.

You could very well do a similar workout with the leg press machine, chest press machine, or with pull ups or burpees.

Just whack the weight up high and pump out as many reps are you can for 30 seconds then rest.

Mix it up!

And… rest

So that’s a brief summary of all that.

I do apologise for bombarding you with science but I’m fed up of seeing people wasting their lives endlessly puffing away on cardio equipment.

Make it quick and painful and you’ll see far better results than if you sit on the arm bike for endless hours.

Get home to your friends and family, or failing that a pot noodle and a wank, rather than wasting your life in the cardio room.

Let us know how you get on with this, and I hope you achieve abs so hard people will nickname you wash-board.

Stick with it and I promise you results.

It even works for fitness.

Further reading

If you want to read more on all this information, pick up a book called Body By Science by John Little and Doug McGuff, props to them!

Leave a comment below and, as always, keep lifting!

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  1. I agree with a lot of what you said in here.

    While I like my long runs every once in a while, I have a tough time justifying them because I can get better results with HIIT training and it takes much less time.

    I have seen the negative effect on gains because of my running habits as well.

    These days, I use the treadmill, but in 20 minute bursts of HIIT running switching between sprints and jogs.

  2. I do not believe that cardio is dead.

    HIIT training for instance with adjustable dumbbells is still cool if done right.

    1. Did you even read the article?!