Does Running Kill Muscle Gains? Or Does It Actually Help!

It’s commonly thought that “cardio will kill your gains” but is that accurate? Cardio will not kill muscle. However, doing too much cardio and not enough strength training is a surefire way to decrease muscle mass. And cardio on its own will not lead to significant muscle gains without any added strength training.

So what’s a runner to do – especially if they want to maintain their muscle size and strength?

Does Running Kill Upper Body Gains?

No, running alone won’t kill your upper body gains. However, if you completely stop doing strength training as you increase your running, you will likely notice a decrease in the size of your muscles. This is because you are not stimulating them with weight lifting while you’re simultaneously burning more calories, which can lead to overall weight loss (including muscle mass).

If you have added running into your weight training routine, then you likely won’t notice a significant change unless you are so tired from running that you’re unable to put in the hard work in the gym (Source).

It will also be very important to continue to eat enough food to aid in both recovery and muscle growth while you combine running and strength training.

In addition, upper body muscles may be easy to maintain while you’re running because your arms won’t be particularly fatigued from your runs. Plus, burning the extra calories from running may help showcase those hard-earned triceps, biceps, and delts, so it’s ultimately a win-win.

Is Running Bad for Muscle Gain?

Fortunately, running is not inherently bad for muscle gain. In fact, in some instances, it may even promote it. High-intensity interval training (HIIT) and sprints have been shown to increase muscle fibers in the legs, particularly the quads. (Source)

On the other end of the spectrum, long-distance running has the potential to hinder muscle growth. This is at least partially due to the amount of time required to put in the effort to build a base for those long endurance runs.

It is very challenging to juggle the demands of long-distance running with a solid strength training regime, not to mention the stress the body goes through during those runs.

If you are really concerned about cardio killing your muscle gains, you can always incorporate a lower-intensity form of aerobic exercise into your routine.

Activities like cycling, swimming, and rowing can be a great supplement to your strength training goals.

These are low-impact and full-body exercises that can complement many different types of weight lifting plans. In fact, it’s just as bad for lifters to completely skip cardio as it is for runners to skip hitting the gym.

You will want to make sure you have a well-rounded routine that encompasses cardio and strength in order to keep your body healthy for the long haul.

Does Running Destroy Muscle?

Running is not often the direct cause of muscle destruction, but you may experience some muscle loss if you’re running often. Your rate of muscle growth may slow if it begins to interfere with your weight training efforts (Source).

Here are a few ways you can mitigate any muscle loss as a runner:

  • Keep the volume relatively low (2-3 runs per week that last around 30-45 minutes)
  • Separate the days you do cardio and strength training, if at all possible, to help with recovery
  • Find a strength training routine that complements your running, rather than competing with it (i.e. no heavy squats before your long run day)

Another important thing to be aware of is proper fueling

If you are running so much that you end up in a chronic caloric deficit, your body may begin “eating” its own muscle for energy. That’s why it’s incredibly important to make sure you’re eating enough for all of the activities you’re doing. This will aid in keeping your body healthy and lessen your risk for injury.

Should I Run if I’m Trying to Build Muscle?

Yes, running can be a useful exercise to add to your routine if you’re trying to build muscle. However, it can help to first figure out what your priorities are.

If you’re mainly looking to grow muscle, then your running will need to be a secondary activity. This means you likely won’t be hitting any speed or distance PRs while you’re in your strength training phase.

It can be helpful to think of your training as seasons. These can be figurative or literal seasons. For example, if you don’t enjoy running outside in the dark of winter, you can use that time to focus on your strength training efforts.

You’ll still want to run when you can to keep your cardiovascular health strong, but it should be majorly scaled back from your peak. This can also be a great time to work on other skills like agility and mobility, or even to try something completely different.

Does Running Help in Gaining Muscle?

You can definitely gain muscle from running, though it won’t be at the same rate you’d build it from weight lifting. The muscle you’ll gain from running will primarily be in your legs, specifically in the quads, hamstrings, and calf muscles. (Source)

You may also notice some muscle changes in your glutes (especially if you’re using the proper form). If you only run, though, you likely won’t see a major increase in muscle mass.

If that’s one of your goals, you’ll want to find a targeted weight training plan that focuses on progressive overload. There are some plans that can work with your cardio training, but be careful not to overdo it.

More to Consider

Running and muscle growth are not mutually exclusive, but it’s important to do it right. Your first step is to figure out your main goal, which will help you prioritize one over the other.

And make sure you leave plenty of time for rest and recovery along with the necessary fuel to do all of your activities.

Aprill Emig

Based out of Duluth, MN Aprill loves to write about the outdoors, education, and all forms of adventure. You can find her mountain biking, running, or playing roller derby.

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