“Cardio”…Is It Optimal? Part 1


When I say “cardio” I’m talking about your traditional forms of cardio. Jogging for 30 minutes to and hour, cycling, walking on an incline, etc. So what does this kind of cardio actually do?

In Part 1 of this blog post, I will look at traditional cardio, and what it does.


The Good: 

Traditional, or steady state cardio will increase your aerobic threshold and help your body adapt to running/cycling longer distances. As you progressively increase your time or distance spent jogging, you will be able to go longer, easier. I remember when I couldn’t run more than a mile without slowing down to catch my breath.

In one month of training leading up to my first “running event”, I started my first week by just running for 10 minutes straight everyday. My second week I upped it to 15, then 20 minutes. Then I started to go by distance. 3 miles 4 days a week the 3rd week, and 4 miles the fourth. In one month I went from barely being able to run a mile to running 5 in 42 minutes. Steady state cardio is great for this! The body is amazing and can adapt so quickly.

But that may be where the benefits end…

The Maybe:

I say maybe, because depending on your goals, it might be bad or it might not be. Steady state cardio can lead to weight loss. However, it might not be the kind of weight loss you want. Depending on your goals, you may end up losing more muscle mass than you want. Without changing my diet, I dropped down to under 200 pounds for the first time in 6 years. However, my arms were thinner, my face looked almost sickly thin.

Look at distance runners. They are very thin (typically) and have little fat and muscle mass. This is perfect for them though because as you run longer distances, you don’t want to be carrying around tons of extra mass.


The Ugly:

Looking more at the recreational exerciser or weight loss adventurer, using steady state cardio may prove to be less effective over time. It has been shown that long-term (1 to 2 months) of steady state cardio sessions can actually cause a negative metabolic adaptation.

What does this mean?

If you continue to do your 30 to 60 minute steady state low intensity sessions 3 to 4 days a week, your metabolism may actually adjust to this, blunting weight loss. I have seen this first hand through working in the fitness industry for the last 6 years. While the adaptation to running long distance can be great for your cardio endurance, it may not be the best for fat loss. This is because the body becomes more efficient at conserving calories for longer durations, thus burning less calories – to conserve more energy (in the form of calories). This is why we see many recreational endurance athletes who still hold onto a decent amount of body fat, often times in the form of a little belly pouch. Burning more fat and calories overall is technically done better through inefficiency – by burning more calories per minute (more on this in part 2).

While working at a large campus gym while in college, I got to know many patrons of the gym. Many of them did the standard 30 minute, jogging sessions, and never really changed. I often got complaints about how they weren’t losing the weight they wanted to. (because they were doing the same thing over and over and expecting different results) Granted, at least they were doing something and getting many great benefits of cardiovascular exercise, but it wasn’t optimal for their goals.

They then get into the vicious cycle of lowering their calorie intake (to try and lose weight), and increasing their duration of steady state cardio, until they are essentially starving themselves (800-1000 calorie diets) and this leads to even more negative metabolic adaptations, to the point where their metabolism could slow down by 25-50% of what would be their estimated metabolism!

Woman Holding Hand to Head

But the treadmill said that I need to stay in the “fat burning zone” to burn the most fat!

We have all seen it, cardio machines with the little scale on it based off of heart rate that says “Fat Burning Zone” at about 60 – 70% of our max heart rate. The origin of this zone is not exactly known, but looking through research it seems to have come about from a few studies in the early 90’s.


Yes, performing cardio at about 65% of your “max heart rate” (which is actually based off of a simple, and highly inaccurate equation of 220-Age= MHR) burns the highest % of calories from fat, AT THE TIME OF EXERCISE*. Say you burn 200 calories during 30 minutes of cardio in the fat burn zone, and 90% of those calories are fat calories (180 calories). But what if you increase the difficulty to 75% of your MHR and burn 275 total calories, but only 75% of those calories are fat calories? You are still burning about 205 fat calories, just a lower % of total calories. (Hint: more calories burned is better)

*This is also an ACUTE response measurement, not a long term response. Why should it matter what you burn only during exercise, when it is more optimal and advantageous to burn more overall calories (especially from fat) throughout the day by revving up your metabolism?

So if I want to lose fat more efficiently, and not lose muscle, what should I do?

Remember, if your goal is to train for a distance event, whether its a 5k, half marathon, or Iron Man, keep doing steady state cardio. Your body will adapt and you will be able to run longer over time.

But, if your main goal is fat loss, increasing daily metabolism, then stay tuned for Part 2! 

Published by Mike Gorski

Registered Dietitian and Fitness Coach OWNER OF MG FIT LIFE LLC

2 thoughts on ““Cardio”…Is It Optimal? Part 1

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: