Does Cardio Kill Gains?

Does Cardio Kill Gains?


January 22, 2022

Are resistance training and aerobic exercises mutually exclusive? Should you avoid cardio if you want to build impressive muscles?

Put differently; does cardio kill gains?

Many people who would like to build muscles tend to shy away from cardio exercises and HIIT classes because they believe that aerobics could make their hard-earned gains go to waste.

Of course, no one wants to spend countless hours sweating it out in the weight room only to lose negate all that hard work with the wrong type of workout.

But is this worry justified? Read on to learn more.

Cardio Kills Gains: Truth or Myth?

Does Cardio Kill Gains?

Many weightlifters and bodybuilders swear by the mantra, “Cardio kills gains,” so they avoid it at all cost.

Indeed, cardio workouts condition the body in a very different – somewhat opposite – way than strength or resistance training.

But the truth is that cardio offers significant benefits, even for people who want to build muscle strength.

It is common for people to associate cardio exercises with only weight loss. While most people do aerobics to lose weight, that’s not the only health benefit you can get from it.

Cardio workouts can improve sleep quality, lower resting blood pressure, and lead to a better mood.

Other positive health benefits include reduced risk for diabetes, improved cholesterol, and enhanced brain function among others.

But regardless of the many benefits of aerobic exercises, some people in the lifting community simply won’t hear of it!

It might be difficult to accept, but completely abstaining from aerobics simply because you are trying to build muscle mass is a misconception.

The simple answer to the question, “Does cardio kill gains?” is an emphatic no! If anything, cardio can boost the effects of resistance training.

In other words, you will be probably missing out on more muscle gains if you avoid cardio like a plaque!

But there’s a catch!

You will have to find the sweet spot where you can get all the positive health benefits of cardio without destroying all the muscles you’ve worked so hard to build.

We’ll get to how you can find that sweet spot in a bit.

For now, let’s look at the science behind losing muscle gains.

Understanding how gains are lost can help you figure out how to better combine cardio with strength training.

The Science Behind Losing Muscle Gains

Does Cardio Kill Gains?

Resistance training or strength training can help grow muscle tissues – a process known as muscle hypertrophy in scientific terms.

It may sound a bit counterintuitive, but muscle hypertrophy or muscle growth actually results from muscle damage. Here’s what that means.

Muscle damage in lifters happens when muscles contract or lengthen under heavy strain.

The body is highly intelligent and as soon as it senses this type of muscle damage, it activates and sends more resources to the damaged muscles.

This will enable the injured muscles to handle the strain better in the future. And that’s what we refer to as muscle gains.

But all or most of the gains can be lost if you do your training incorrectly. Here’s how.

How Cardio Can Interfere with Muscle Gains

Does Cardio Kill Gains?

In 1980, a study showed that combining cardio and strength training over 10 weeks disrupted muscle growth compared to performing strength training alone.

Many people ran wild with the conclusion of this study (which is over four decades old) without taking a closer look at the volume of training the participants were subjected to.

To show that aerobic exercise interfered with resistance training, the controlled group had to do six straight days of cardio per week in addition to five days of strength training weekly!

And the training was done 30 to 40 minutes every day.

It’s easy to see that the volume of training was very high. Not very many people today can afford to spend that amount of time doing cardio six days weekly.

In other words, to lose muscle gains or for cardio to “burn” muscles, you will have to consistently get your training and diet all wrong.

A more recent study conducted in 2012 suggests that doing moderate cardio can enhance the effects of strength training.

What’s more, doing strength training together with about two to three days of cardio can even help you build more muscles than if you were focused on strength training alone.

Can You Avoid Losing Gains With Cardio?

Does Cardio Kill Gains?

Yes, you can combine cardio with strength training without losing gains.

The “trick” is to perform moderate aerobic exercises so they don’t break down the contractile proteins (actin and myosin) that make up the muscle fibers you’ve worked hard to build.

Experts recommend doing cardio at moderate intensity for a total of about two to three hours per week. That’s no more than 45 minutes for each cardio workout.

Low-impact aerobics including cycling, rucking (walking with a loaded backpack), skiing, rowing should rank high among your cardio exercises if you want to maintain muscle gains.

While running is a good form of cardio, it isn’t necessarily the best aerobic exercise to combine with strength training.

And running for hours? Definitely a no-no!

That’s because running can cause too much muscle damage that will interfere with recovery and muscle growth.

Choosing low-impact activities isn’t the only “trick” you should have up your sleeves when combining aerobic exercises with resistance training.

Below are some important tips to help you maintain muscle growth with cardio.

Pro Tips for Boosting Muscle Gains with Cardio

Does Cardio Kill Gains?

Don’t do both kinds of training at a time

It is a common mistake to combine cardio and strength training in the same workout. Many people do this in the form of circuit training or CrossFit.

While there is nothing wrong with circuit training and CrossFit, it is best to do cardio on your rest days if hypertrophy is your primary goal.

Mixing cardio and strength training at a go will not only make it difficult for you to perform at your best, but it also leads to less muscle growth.

If you must do cardio on the same day you lift weights, consider separating your aerobic exercises as far away from your time in the weight room as possible.

For example, if you do strength training in the morning, do cardio in the evening.

The reason for this is simple.

You want to spare your muscle tissues from severe damage.

Choose your workout order

Studies do not show any huge difference when it comes to the order in which you perform your workouts.

The improvement in your muscle size and strength is not really affected by whether you do aerobic exercises before resistance training or vice versa.

That being said, let’s consider the workout order from a more practical perspective.

If you are like most people, your cardio session is less likely to be affected by fatigue from a resistance training session.

For example, you are most likely to complete 30-minute cycling without feeling too drained even after lifting weight earlier in the day.

The reverse is usually the case if you do cardio first.

The fatigue from a cardio workout is more likely to affect your strength training session. This is why most people would rather get exhausted from strength training than running.

Here’s the thing, though.

Everyone is different. So, we recommend trying out the different workout orders to find out what works best for you.

Choose the best aerobic exercises for weightlifters

As already mentioned, you want to limit running (especially long-distance running) if you predominantly want muscle gains. Instead, consider some of these other forms of cardio:


High-Intensity Interval Training (HITT) might not be as difficult as resistance training exercises, but they offer a great balance between sculpted muscle and athletic performance.Do HITT no more than two to three times a week if gains are your main goal.


Let your muscles heal from the stress of lifting heavy weights with short swimming sessions. It is a great total-body workout and won’t risk muscle gains as long as you don’t do it until it triggers your body’s endurance faculties.


This is a less intense way to keep your heart rate up on non-lifting days without jeopardizing all the hard work you put in the weight room. Plus, you can do it for longer periods than running.


If you absolutely want to include running in your workout routine, go with sprints.

In addition to improving the body’s energy regulation, this quick-burst running exercise can speed up your body’s recovery time.


So, does cardio kill gains?

No, it doesn’t.

But if you don’t know how to use cardio correctly, it can interfere with your strength training and make you lose muscle.

A good way to get the best of both worlds would be to do less than an hour’s cardio exercise for about two to three days a week.

Focus on low-impact forms of cardio and make sure to properly separate your strength training and cardio exercises by as much time as possible.

If implemented correctly, cardio can boost muscle gains instead of eroding your hard work.



Justin Rodriguez has spent most of his adult life inspiring people to take their fitness more seriously. He is not new to the business of providing practical solutions for those looking to set and smash their fitness goals. From sharing professional tips and tricks to recommending awesome products, Justin Rodriguez helps just about anyone who wants to get the best out of their workout routines.Having gathered a lot of experience both in and outside the gym, Justin Rodriguez uses DSW Fitness as a medium to show you exactly how to get that great-looking body with toned muscles you’ve always wanted.