By: Chris Gates

You’ve probably heard at least one person say, “cardio is bad for muscle growth.”

You see, the theory is this…

1. You lift weights.
2. And you do cardio.
3. Your body has to recover from both.
4. Cardio limits how much muscle you’re able to build.

And while there’s truth to the fact that your body has to recover from all of your training, there’s also a whole lot of context and nuance that gets lost.

So in this article, I’m going to answer this question for you: is cardio bad for muscle growth?

And I’ll make the answer specific to YOU.

We’ll talk about what the research says on cardio and how it impacts muscle growth, and outline key concepts that you should understand to get the most out of your training.

And by the end, we’ll put all of the pieces together to help you build as much muscle as possible.

So let’s dive in!

Check out some of my amazing clients who transformed their physiques through strength training and cardio to see amazing results!

How Does Muscle Growth Work?

Before we tackle this subject head on, it’s important to discuss how muscle growth actually happens.

Because all of this exercise that you do — lifting, cardio, etc. — is just a stimulus to your body.

1. You train hard.
2. Your brain identifies it.
3. And then your body gets to work to recover, adapt, and grow.

It’s all an effort by your body to make exercise easier in the future. Because your body wants to be as efficient as it possibly can be at all times.

• If lifting is really challenging, your body will try to adapt to make it easier.
• If running has you completely gassed, your body will try to adapt to make it less difficult.

For muscle growth, the process typically starts with a hard strength training session. You lift weights and challenge specific muscle groups.

Once complete, your body starts to repair damaged muscle fibers, and looks to grow new muscle fibers. This is called protein synthesis.

Once again, to make you stronger so that lifting gets easier.

And so that your body gets more efficient.

Is Cardio Bad For Muscle Growth? The “Interference Effect”

The fears that cardio will “kill your gains” started all the way back in the 1980’s.

This study put three different groups of people through specific daily exercise plans for 10 weeks:

1. Strength training only plan.
2. Endurance training only plan.
3. Combination of strength and endurance training.

The group that did both strength and endurance training saw their rate of strength development plateau after seven weeks. So researchers concluded that doing simultaneous strength and endurance training would result in “a reduced capacity to develop strength.”

Additional studies backed those claims up for years. Eventually, a meta-analysis came along in 2012 and helped coin a term for the issues of combining both strength and endurance training.

That term: “the interference effect.”

After examining 21 different studies that compared strength training alone, to strength and endurance training combined (concurrent training), researchers concluded that long-duration cardio will negatively impact strength and power outcomes from lifting weights.

That negative impact was considered “interference.” Cardio interfered with the body’s ability to build as much muscle as possible.

Due to this body of research, it was a pretty understood belief that doing cardio was bad for muscle growth.

New Research Paints A Different Picture

Over the last decade or so, researchers have continued to investigate this topic and have found there’s actually a lot of nuance involved.

Cardio isn’t necessarily bad for muscle growth, as long as you’re organizing your training efficiently.

A 2018 meta-analysis put a lot of fears to rest by explaining that you can split up your strength and cardio training to counteract any type interference.

It seems that the nature of the cardio you do makes an impact. If you’re doing very high-intensity cardio, you could run into issues where your strength training performance is impacted.

Long-duration cardio could also have an impact on your strength training, and impair muscle growth.

But again, splitting things up seems to make a big difference and more or less negate any “interference” or recovery issues for muscle growth. It’s as simple as this…

• Do cardio and strength training on different days, or…
• Separate them within the same day by six hours or more.

Scheduling will help you prevent a lot of the potential issues, and below I’ll help you map out a schedule of your own!

The MASS Research Review has a really helpful chart on how you can mix cardio and strength training to minimize the interference effect with recovery.

Is Cardio Bad For Muscle Growth?

In general, no.

For the average lifter that wants to build muscle, you really don’t need to overthink this. Unless lifting weights is your job, or you’re training for some type of high-level competition (powerlifting meet, marathon, etc.), this tends to be a non-issue.

The negative impact cardio may have on your muscle growth is so limited that it’s almost microscopic.

But if you’re really concerned about structuring things as optimal as possible, there are a few things you can do.

There can be “interference” if you’re doing extremely intense, or extremely long-duration cardio. But even if that’s the case, you can still grow muscle — it just may be slightly less than optimal results.

If muscle growth is your primary goal, you should prioritize your strength training and sprinkle in cardio in ways that won’t take away from your lifting performance.

For example:

• Do cardio on your off-days from lifting.
• If you have to do cardio on lifting days, do it after you lift.
• If possible, make the cardio on your lifting days low-intensity and/or low-impact.
• If you’re forced to do both strength training and cardio on the same day, and both are intense, try to space them apart as much as possible (ideally six hours or more).

Prioritize lifting so that you can prioritize your muscle growth.

Don’t do sprints before you lift weights. And don’t be doing burpees during your rest periods in between each set.

Let cardio fall into your program in a way that makes sense.

Is Cardio Bad For Muscle Growth? Or Is It Actually Good?

We’ve focused so much on whether or not cardio is bad for muscle growth. But could it actually enhance muscle growth?

It’s possible.

There’s evidence that low-intensity cardio following strength training can increase blood flow throughout the body, which will help deliver nutrients more quickly to the muscle groups in need of recovery.

In general, low-impact forms of cardio like walking or cycling seem to be better than high-impact forms like running.

There’s even some emerging research suggesting cardio before lifting could actually enhance the body’s rate of protein synthesis. And while this isn’t what I’d recommend you do if muscle growth is your primary goal, it’s certainly interesting.

Example Workout Schedule

It’s hard to give a workout template that’s going to work for everyone, which is why I don’t sell templates. I work with people 1-on-1 to build muscle, burn fat, and improve their health.

But as an example, here’s what a weekly workout schedule might look like for you to build muscle and also do regular cardio.

Day:	Workout:	Notes:
Monday	Upper Body	Low-intensity cardio after lifting (optional).
Tuesday	Lower Body	Low-intensity cardio after lifting (optional).
Wednesday	Low-Impact Cardio	Walking, cycling, elliptical, or some other low-impact form of cardio.
Thursday	Upper Body	Low-intensity cardio after lifting (optional).
Friday	Lower Body	Low-intensity cardio after lifting (optional).
Saturday	Rest	Full day off.
Sunday	High-Intensity/Duration Cardio	This is your high-intensity, or long-duration cardio day, as it will have the least interference with the rest of your program.

As you can see, there’s room for cardio on virtually every day of the week, but the nature of that cardio varies.

• On days you strength train, you’re doing low-intensity cardio. It comes after you lift weights to allow you to put all of your energy into lifting.
• On non-lifting days, there’s time for more long-duration or high-intensity cardio.
• That Wednesday cardio session is focused on low-impact forms of cardio in order to reduce the recovery demands on your body. Since it’s sandwiched in between multiple lifting days, this will keep your body as fresh as possible.

Designing a workout routine is kind of an art. You take your primary goal, make it the focal point of your program, and then complement it with other forms of exercise that you enjoy and support your secondary goals.

It’s kind of like when Bob Ross would create a painting and fill it with happy little trees. (OK, that’s a ridiculous metaphor, I know haha.)

But keep this in mind when you’re putting your own routine together. If your primary goal is to build muscle, structure your workouts accordingly.

Is Cardio Bad For Muscle Growth? Not If You’re Smart About It

Thanks so much for stopping by and reading this article! I hope you found it helpful 🙂

As you can probably tell, the way you structure things is going to be very specific to you, your lifestyle, and your goals.

But in the end, you absolutely can combine cardio and lifting to see amazing results with muscle growth!

And honestly, I’d encourage you to do so. Because the health benefits of doing regular cardio are far too valuable to pass up.

If you have any questions about how to structure your routine, please don’t hesitate to reach out! I’m always happy to help.

Also, if you’re interested in getting coaching to help you maximize your results with muscle growth, that’s what I do! I work with people all over the world to build muscle, burn fat, and improve their health.

Head over to my coaching page to learn more.

~ Chris