Cardio is Dead, long live Cardio

It is becoming popular to bash cardio activities and I am not really sure why.

  • doesn’t build muscle
  • doesn’t cut weight
  • your body gets used to it so it will have no effect

At the end of the day, if your goal is to become a body builder then of course cardio is not the thing you should do. But it you want to improve your fitness then why would you be against any form of physical activity?

The more specific push back I have heard is that your body gets used to cardio and you stop losing weight, improving, getting healthy, whatever.

Being a runner and triathlete I obviously have some bias. I am also a personal trainer and yoga instructor, so I have some level of knowledge in both areas.

The main implication is that cardio (whatever that means to you) will not lean you out, or will, over time, provide less and less weight loss benefit.

The issue with cardio is one of definition. People equate running, jogging and biking type activities with cardio, but the reality is that anything that gets your heart rate elevated for an extended period of time can be considered cardio.

But remember, the converse is also true…if you perform traditional cardio exercises and do not achieve an elevated heart rate then you are not doing a cardio exercise.

The key word here is INTENSITY!


  • Jogging, 5km/h – 60 mins, 450 calories
  • Running, 10km/h – 60 mins, 730 calories
  • Running, 15 km/h – 60 mins, 1400 calories

If you jog 5km in an hour then eat like you ran 15 km in that same hour you are just asking to gain weight!

At the end of the day it is basic math, calories in versus calories out, and yes I am aware that it is more complicated than that, but it also isn’t that complicated.

When doing cardio-like activities there is no guarantee that you are burning enough calories to lose weight. If you are not cardio-ing as hard as you think you are…you are not burning as many calories as you think and, surprise surprise, you are not leaning out as much as you think you should.

I see this all the time, people go and do a lunch hour or after work fitness class of some description, then consume a protein shake containing 350 calories…and then head home for lunch or dinner. The result is actually a negative impact on their weight. They may be toning up but they will not be leaning out.

And some of the statements you hear from people are incredibly misleading…for example…

“I did a really hard triathlon workout […] nine-hour session […] 10-mile run, 70-mile bike ride, and finish with another 4-mile run, but I gained weight over time as I was doing this”.

First off, let us not downplay the amazing accomplishment that is the 9 hour workout. It requires incredible focus, dedication and perseverance.

However, let us actually break down the numbers…

  • 10 mile run (16km for those Canadian’s in the crowd)
  • 70 mile bike (112km)
  • 4 mile run (6.5 km)
  • Total 9 hrs

At my fastest my time for doing that type of workout would be (1hr + 3.5 hrs + 30 mins), call it 5.5 hrs to be generous. Yet some people are taking 8 or 9 hrs for the same distance, obviously a less INTENSE session.

An important follow up questions, how many calories are consumed during the 9 hour workout? Is this added into the total for the day or the week? I am going to suggest that most people do not count the calories consumed during a long cardio workout (gatorade, power bars, gel packs) yet this total is VERY significant. You are literally unable to do a 8 hour workout without significant calorie intake during the session.

It is true that aerobic capacity (cardio efficiency) is greatly increased by the amount of aerobic (cardio) exercise you do and yes, your body will get more efficient and burn less total calories. But isn’t that the end goal of aerobic (cardio) training? You are training your body to be efficient and perform to and beyond it’s current limits.

People will tell you they didn’t lose weight running but lost weight doing crossfit, so crossfit is better.

I will come back to my original comment, it is all about intensity.

When you are doing a crossfit class, you are constantly striving to lift heavier weights, to do more burpies or pull ups. To do more push-ups in 10 mins or whatever. The intensity of the workout is constantly increasing.

Rarely to people try to increase the intensity of their cardio activities. If I run my 10k on Saturday in the same time, always, then of course my body is going to get good at that activity. I will be in decent shape but my body will adjust.

It is important to compare apples to apples. If you want to push yourself in cardio activities then try to run faster each week, or longer or both, but being complacent will get you into a mode that burns less and less.

But remember – Any activity is good activity!!!!

It really is simple

  • Get active
  • Pick an activity that you can enjoy over days/weeks/months so you don’t get bored
  • Gradually Increase your intensity, challenge yourself always.
  • Eat the proper number of calories for the level of intensity you are performing.

You will lean out, regardless of the workout you are doing.

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