Does Running Burn Muscle? - Madaboutrun

Does Running Burn Muscle?

It only takes a quick look at the physiques of professional long-distance runners to give credence to the assumption that running doesn’t just burn fat, but muscle too.

Then, to confuse things, you’ll see short distance runners with huge, rippling muscles, so what’s really going on here. Is the idea that running burns muscle a myth, or is there some truth to the statement?

Well, to answer the question as quickly as possible, yes. Intensive running can indeed eat into your muscle protein reserves, but that’s not to say that you should completely cut it from your exercise regime if you’re trying to bulk up.

It’s actually quite a complex topic, so before we discuss how you can keep muscle loss to a minimum when running, we’ll need to take a closer look at why it happens in the first place.

Why Does Running Burn Muscle?

It doesn’t matter what kind of exercise you’re doing, your body always pulls its energy from the same three classes of molecular fuels, proteins, carbohydrates, and lipids. These classes include fat reserves, blood sugar, muscle glycogen, and, of course, muscle protein.

All these energy sources work as a team to keep you going when you’re feeling the burn during a workout, and it’s up to you to formulate a diet that keeps each one of them sufficiently juiced.

When you’re undernourished and one of these energy reserves runs dry, it puts extra strain on the remaining sources as they try to fill the energy quota and keep you running, jumping, or lifting at full capacity.

The remaining energy sources don’t particularly mind covering for their down-and-out buddy, but the harder they have to work, the faster their reserves deplete. One by one, they run dry, and eventually, the onus falls on your muscle protein. It may be able to pick up the slack for a small amount of time, but the more your body utilizes, the less your muscles receive after the fact for recuperation and growth.

It works both ways, too. For example, if you start your exercise with low levels of muscle protein, your body will eat up what little there is, forcing the other energy sources, such as blood sugar and fat, into overdrive.

Why You Shouldn’t Stop Doing Cardio When Trying to Build Muscle Mass?

I know the whole running-burns-muscle revelation can be alarming, especially if your main fitness goals involve hulking out a bit, but there are a number of reasons that you shouldn’t scribble out that run on your exercise plan.

Organ Health

Running may burn off a fraction of your skeletal muscles by dipping into their protein reserves, but what it doesn’t weaken is your heart.

The more you run, the healthier and stronger your heart becomes, and the healthier your heart is, the further you can push yourself with other fitness endeavors such as weight training.

The lungs also benefit greatly from cardio exercise, and as I’m sure you’re aware, muscles require a significant amount of oxygen to function properly, and the larger they get, the more oxygen they need.

So, if you want your muscles to be as powerful as they look, going on the odd run around the block is the answer.


It’s a fact that running can help build endurance, not just when you’re stomping pavement, but in every physical activity you take on. If you want to add a few reps to your bicep curls, the endurance built up from running can help you do that.

Burning Fat

Did you know that there’s no such thing as “toning” muscles? Muscles are either getting bigger or smaller — that’s it. The only other factor affecting how they look is the fatty tissue in the area.

It’s actually the burning off of these residual fat tissues that gives muscles that “toned” appearance, and running is one of the most effective ways to burn body fat.

Mental Health

Running isn’t just great for our physical health. As a proven de-stresser, it can also be hugely beneficial to our psychological wellbeing too, especially if a route helps us to get out and away from the hustle and bustle and reconnect with nature.

How to Keep Muscle Loss to a Minimum When Running?

Fortunately, there are a couple of measures we can take to reduce the negative impact running can have on our muscle mass.

Nutrition Plan

As we’ve already discussed, when one energy source runs dry, the others have to work even harder to fill in for their depleted comrade. So, if you want to minimize the amount of muscle protein your body uses during a run, it’s essential that you keep all your energy sources topped up.

Now, I’m not saying that you need to eat a full three-course meal before you hit the track. That will only lead to vom city. However, eating responsibly the day before and the day of a run is key.

Topping up your electrolytes and glycogen levels by sipping on a sports drink mid-run will also help to reduce the tax on muscle protein a great deal.

Post Work-Out Meals

It’s not just before and during your run that you need to implement some sort of dietary strategy. Eating the correct food after exercise is also essential if you want to maximize your gains.

It’s a wonderful opportunity to treat yourself to all the high-fiber carbs and proteins you love such as peanut butter, grilled vegetables, chicken, salmon…whatever floats your boat.

Weight Training

Even though proper diet can more or less bring muscle loss during cardio to a halt, you’re not going to see any gains unless you actually do exercises that focus on building muscle rather than just burning fat. It’s very much an “if you’re not gaining, you’re losing” situation, so grab those dumbbells and get to work!

Summing Up

There you have it, fellow fitness-heads. It’s true, running can burn muscle, but as long as you keep all three classes of energy reserves topped up with proper diet, and supplement your exercise regime with plenty of weight training, you’ll bulk up in no time!

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