Does Aerobic Exercise Increase Muscle Mass?

Researchers examined the effects of aerobic exercise on muscle mass. And the findings might give you another reason to keep running.


  • A recent study looked at the effects of aerobic exercise on muscle mass and found that while it doesn’t help to build muscle, it can help maintain it.
  • Researchers and experts suggest strength training and focusing on nutrition to help support muscle growth.

Regular running provides a breadth of benefits, from improved cardiovascular health to better emotional health. But can it also boost your muscle mass?

Unfortunately not, according to new research in Medicine & Science in Sports & Exercise. But it can help you maintain the muscle mass you already have — which is a major advantage, given that we all lose muscle mass as part of the ageing process.

To determine the effects of aerobic exercise on muscle mass overall, as well as muscle in specific areas of the body, researchers measured muscle and fat tissue in 238 men and women, then asked 175 of them (the rest were a control group) to walk on a treadmill at moderate-to-vigorous intensity weekly for between 12 to 24 weeks.

They found that those in the walking group tended to preserve muscle mass compared to control group participants — but they didn’t increase that mass even if they continued walking for the full 24 weeks.

“The takeaway here is that there are a wide range of health outcomes that come from participation in regular aerobic exercise, and we can add maintenance of skeletal muscle mass to those benefits,” lead author Dr Robert Ross, researcher at the School of Kinesiology and Health Studies at Queen’s University, Canada, told Runner’s World. “This is good news for older persons in particular, considering the age-associated loss of skeletal muscle.”

He added that participants’ nutrition was also tracked, and that the highest level of muscle mass preservation was seen with those who consumed adequate amounts of protein. (The International Association of Athletics Federations (IAAF) recommends that endurance athletes, like runners, consume between 1.6 to 2.2 grams per kilogram of  body weight.)

Getting motivated to build muscle is helpful, but how do you actually get started and maintain progress with increasing your muscle mass? The answer comes with numerous individual variables — including nutrition, sleep, and overall activity levels — but beginning with strength training two to three times weekly is a good goal, suggested strength and conditioning trainer Reda Elmardi.

The focus should be on exercises that target the entire body, including your core muscles, legs, shoulders, and back, he told Runner’s World. You can tweak a strength program to address a certain set of muscles one day per week — for instance, only doing exercises for the lower body — then another day will be about upper-body muscles. Also, be sure to include at least 24 to 48 hours between your sessions, especially if you’re new to strength work, he added.

“What you’re looking to do is create stress on the muscles, which creates minor damage in the muscle fibres,” said Elmardi. “As this damage is repaired during a rest day, it leads to improved muscle function, as well as more muscle mass.”

That pairs well with maintaining those gains through aerobic activity such as running or cycling, and you’ll boost your endurance along the way, too.

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