The Death of Cardio


By Taylor Robbins, C.S.C.S
You may be wondering why the heck this article is called the Death of Cardio.  Well, I really do think cardio needs to be placed in a guillotine and decapitated for treason.
But really, without the grotesque metaphors, cardio should not be a part of a fat loss program anymore, nor should it be considered for any health or body composition improvements.
First, let me ask this, most of you exercise and diet to get into good shape, right?  You want to look better in your clothes, in the mirror, and let’s be frank…naked.
Additionally, you want to have better levels of health; things such as:

  • Less risk for cardiac diseases
  • Improved blood sugar
  • Lowered cholesterol
  • Better glucose tolerance
  • Less joint pain
  • lowered blood pressure
  • and so on…

Well, it is very apparent through my own anecdotal evidence with clients and through research that if you want these aforementioned things, you can kill cardio right now.
Let’s discuss why.
Cardio should die in replacement of strength training (lifting weights) and HIIT (high intensity interval training) or SIT (sprint interval training).
Improving your body composition comes down to losing body fat and increasing lean muscle tissue.  Period.
In order for this phenomenon to happen, muscle fibers must be stimulated in a progressive fashion, hence the weights, and the right hormones and physiological environment must be created in the body for fat loss.
For the intents and purposes of this article, let’s just look at cardio itself to see how it is affecting your body.
Cardio raises cortisol levels exponentially more than HIIT and SIT and weight training.
A study from 1976 in the Journal of Applied Physiology found two times the cortisol at 30 min of exercise (75% intensity) compared to 10 min doing intervals at near 95%.
Cortisol is our stress hormone.  Whenever we are in our fight or flight mechanism of the nervous system, we secrete this hormone to combat inflammation.  Exercise induces this hormone.  And actually, the more you have DURING exercise, the better.  But, if cortisol becomes chronic and lingers too long, a cascade of events begin to happen:


  • Inflamed gut leading to digestive issues and partitioning nutrients improperly
  • Fat accumulation to facilitate the excess inflammation
  • Loss of muscle tissue
  • Worsened glucose tolerance (a.k.a. carbs become fat more easily)

Now, in discussing hormones, testosterone plays a big role in destroying fat and building muscle.  Let’s just say testosterone is the Captain America to the cortisol being the Winter Soldier (action movie correlations are a must for me).
You want a favorable testosterone to cortisol ratio for fat loss and muscle gain during exercise.  Basically, you don’t want cortisol getting too high in respect to testosterone.  
Testosterone peaks at 20-30 minutes of exercise while cortisol continues to rise throughout the duration of exercise.  This is why long training bouts (aka running for a long time) creates an unfavorable ratio, especially since cardio has almost no testosterone spike at all.
So, your hormones suck when doing cardio for building muscle and losing fat.
Here is my next point: all I ever hear from people is, “I don’t have time to exercise.  I have 18 kids and 4 jobs and there is just no time in the day for me to exercise.”
As ridiculous as it sounds every time I hear it, the truth is you have time to watch two hours of Grey’s Anatomy every day and to get your nails done once a week so you can have those cute little polka-dots on the ring fingernail.
My point is, people complain of time being a factor to their fitness endeavors.
Well, steady-state cardio takes more time for training with less of an effect than HIIT or resistance training.
In fact, one of the popular biomarkers for cardio health is the VO2 max.  This indicates the measure of the maximum volume of oxygen that a person can use.  Basically, the better cardio you have, the more oxygen you can use.
Many studies indicate that VO2 max increases more and faster with HIIT and SIT.
When looking at aerobic capacity biomarkers, a study by the Journal of Applied Physiology saw HIIT trainees who trained for 2 hours over two weeks had improved more than steady-state cardio distance runners who had to run 10 hours over those 2 weeks.
You see, even though one is not training in the “aerobic system” with sprint or interval training, they are still in fact improving in their aerobic performance.
A study from 2005 in the Journal of Applied Physiology saw participants double their endurance capacity from 26 to 51 minutes in 2 weeks by performing only 6 sessions of 4-7 sprints (30-seconds).
When looking at aerobic capacity biomarkers, HIIT trainees who trained for 2 hours over two weeks had improved more than steady-state cardio distance runners who had to run 10 hours over those 2 weeks.
I think it’s safe to say that intervals or sprint training is a better time saver than the jogging or running.
Now, you may be asking, well what if I am really overweight and I can’t sprint very well, or moving at a high intensity is difficult for me.
Even overweight and obese people were studied using either continuous walking or interval power walking.  The interval group increased their vo2 max by 16-19% whereas the continuous walking group saw no increase.
Now look, if you really enjoy distance running, by all means, keep doing it.  You just won’t look as lean and tone as you want to and you will spend about 5 times the time to improve your health.  If that’s you goal, go for it.
Let’s wrap this thing up.
Steady-state cardio like running on the treadmill or jogging does not increase muscle tone, definition, or size, and it actually can increase body fat over time.
Cardio also takes about 5 times the amount of time as interval (HIIT) or sprint training (SIT) takes and it actually improves aerobic health biomarkers less than these other modalities.
To all this, I say to cardio with a Russian accent…
“If he dies…he dies.”

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