Is Cardio Good or Bad For You?

sweatybettyIf you follow fitness media, you’ll see that when it comes to recommendations for exercise and nutrition, there rarely seems to be middle ground. This is particularly true with mainstream popular media: after all, bold, urgent-sounding declarations often get us to click the link, open the magazine, or stay tuned after the commercial break.

I mean, what would you be more inclined to click?

Running on the treadmill is making you fat!


In this 2008 study, researchers found that with 10 untrained collegiate women, strength training alone vs. cardiovascular exercise alone induced a statistically significant percentage of body fat dropped over a 6 week period. However, another study, published in 2009, found that in fact, outcomes were similar in the two groups given an additional intervention of…

By the way I just made that last one up. But you probably barely made it through reading it. Maybe you even glanced away from the screen or opened up Instagram to look at some cats. I don’t blame you.


Simple, direct answers appeal to us. But if you can come away with anything today, please understand that in fitness, a truthful explanation is very often “it depends”.

To make matters worse, fitness professionals often cling to the latest piece of research that emerges. They fail to fully evaluate studies or weigh new research within the greater scope of existing evidence. This is partly because reading all of that research is a huge pain in the ass. What unfortunately results is a pendulum that swings wildly from one extreme to the next.

Cardio is a perfect example:

Cardio burns the most fat!
Cardio makes you fat!

I know, that’s aggravating. But it’s what happens. Fear not, however, because I can untangle some of the mystique around cardio and give you advice. So buckle up and read on. I’ll try to make this almost as pleasurable as a Ryan Gosling meme. Hey girl, hey.


What Cardio Is
Cardio, i.e. cardiovascular exercise, is simply exercise that is rhythmic in nature, is continually maintained (instead of short, intense work/rest intervals),  works large groups of muscles, and elevates your heart rate to a degree that it improves increased use of oxygen in order to improve the body’s capacity of the cardiovascular system.

Clear as mud?

Your body uses different energy pathways to get stuff done. Certain kinds of exercise utilize particular pathways. Cardio uses the aerobic energy pathway.

That’s not very freaking useful either, is it? Instead, let’s talk about what’s important:

What cardio does:
it makes your heart work better, strengthens your bones (if you choose weight bearing exercises like walking), and burns calories. There are other benefits too, but that’s the basic gist.

Stuff that we do that is typically “cardio”: activities like running, walking, swimming, or dance cleaning for starters. (Don’t mock me, it’s my favorite cardio option).


What Often Gets Played Out
Two opposite types often show up at the gym:

The cardio bunny:
this term is kind of sexist. Ok, it’s really sexist, because I see plenty of dudes toiling away on the elliptical for hours too. But these people believe that they must do tons of cardio to unlock their next achievement. They also often equate a good workout only with total calories burned: sounds like a drag to me. But the term is also used by smug gym rats who post too much on Instagram. So that alone makes me want to go for a jog sometimes.

The powerlifter: I had an old school powerlifting vet come up to me once and caution me to not do any cardio. He warned that I might lose my muscle. Yeah, not so much. It takes a lot of time spent doing cardio to negatively impact muscle growth and strength performance. There is some truth to this idea, but my few walks I do each week are only helping my overall performance, not harming it.

As evidence emerges, we’ve found that cardio doesn’t actually reign supreme when it comes to fat loss. 1 Can you lose fat doing only cardio? It’s possible. Fat loss happens when you burn more calories than you take in. But unless you’re also controlling your food intake, you’re going to have to do a hell of a lot of cardio to create a significant calorie deficit.

Moving Beyond Cardio
Cardio burns calories. Yet it doesn’t build muscle the way that some other forms of exercise can offer, especially strength training.

But why care about building muscle, you ask? We care because having more muscle makes fat loss easier. I’ll avoid a long, sciencey explanation and boil it down to this: more lean muscle improves your metabolism. Strength training reigns supreme for building muscle. Metabolic conditioning relies on large muscle groups doing intense work as well, offering some strength benefit as well as torching calories by working at intense pace. The loads are typically less than what we use for strength training, total training time is relatively short, and rest intervals are often incorporated so that work can be harder in effort than what we do with aerobic exercise. 2

The fitness bandwagon has also veered heavily toward favoring strength and high intensity exercise for fat loss because of a mechanism called “EPOC”, or exercise post-oxygen consumption. It just refers to calories you burn AFTER you stop exercising. Strength training and metabolic conditioning have a higher rate of EPOC than cardio. However, the benefit has been somewhat overblown. But that doesn’t stop people from screaming that cardio is now useless for fat loss.

Side note: if you’re doing “HIIT” for 45 minutes, you’re actually doing cardio. The intensity of metabolic conditioning or high intensity intervals can’t be sustained for a long time. Also please, for the love of God, stop calling things Tabatas. You’re not doing a Tabata. I promise. 

Michelle Obama Arms and the Fat Loss Plan


Most clients who come to me with a fat loss goal say they want to lose fat but they also mention that want to change how their body looks. I call this the “Michelle Obama Wish”, because I’ve had several clients mention her arms as something they want. I can’t blame them. The First Lady has some sweet looking guns. She is strong!

If we just lose fat by burning calories and reducing calories, we’ll typically look like a smaller version of ourselves. This is neither good nor bad. But if it’s muscular definition you’re after, get thee to a weight room on a regular basis.

Can You Lose Fat With No Cardio?
Yes. But I don’t recommend eliminating it entirely. Read on to learn why. 

So Why Bother With Cardio?
Because it’s good for you, that’s why. Like eating your vegetables. It also helps you move better, be able to get through tasks like climbing a flight of stairs more easily, and it feels awesome. It’s a huge mood booster! It floods us with endorphins that feel pretty fantasic. It also burns extra calories. If you’re trying to lose body fat, you can use it to boost your calorie deficit.

Also note: going hard with intense strength training and metabolic conditioning cannot be a daily thing for most people. You need rest to recover and build muscle. Light to moderate intensity cardio is a wonderful way to get in some extra activity without burning out.
It’s also restorative: when your muscles are sore and tight, go for a walk. You’ll feel better.
TL;DR: Cardio isn’t the end all be all. It’s also not going to get in the way of your progress, whether it’s fat loss or making gainz in the weight room. Just use it appropriately.

My Recommendations
Evaluate your current use of cardio this way:
-Am I using it mostly as a calorie burning tool? If so, am I using it excessively to attempt to overcome a diet with excess calories, or am I using it to give myself a boost?

-Do I actually like my activity? If not, then why am I doing it?
-Does it move me toward a particular goal? If so, why and how?

The amount we do, the number of days we do it, and the mode we choose is variable: we just have to figure out why we’re using it in the first place and the other pieces will fall into place.

Want an approachable yet scientifically sound approach to fat loss? Sign up for my newsletter and I’ll give you my free book Fat Loss on a Budget. Look for it in your inbox! 



  1. Bryner RW, Ullrich IH, Sauers J, Donley D, Hornsby G, Kolar M, Yeater R. Effects of resistance vs. aerobic training combined with an 800 calorie liquid diet on lean body mass and resting metabolic rate. Journal of the American College of Nutrition. 1999 Apr;18(2):115-21.
  2. Talanian, Galloway et al. Two weeks of High-Intensity Aerobic Interval Training increases the capacity for fat oxidation during exercise in women. Journal of Applied Physiology (December 14, 2006).

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