The Purpose of Inflammation in Muscle Growth

The Purpose of Inflammation in Muscle Growth

You wake up after a tough day at the gym. Your muscles are extremely sore. You might have tweaked your shoulder. The pain isn’t awful, but it’s enough to be noticeable when you put your shirt on.

For a lot of people, the next step is a no-brainer:

Head to the medicine cabinet and pop a couple ibuprofen—also known as a non-steroidal anti-inflammatory drug, or NSAID.

Unfortunately, if you’re trying to get stronger this is probably the last thing you want to do. Research indicates that this common approach to managing aches and pains could be slowing your gym gains.

Inflammation is Bad…Except When It’s Not: The Essential Difference Between Chronic and Acute Inflammation

It’s well-known that chronic inflammation is linked with just about every health problem known to man. Cancer, heart disease, arthritis, Alzheimer’s disease, and even aging itself are all associated with inflammation gone haywire.

Where does chronic inflammation come from? A bunch of things really, especially diets rich in pro-inflammatory foods (like sugar and gluten), diets low in anti-inflammatory foods (like leafy green vegetables and healthy fats), high levels of stress, and environmental toxins.

But while chronic inflammation has gotten so much bad press recently (and for good reason), the other type of inflammation—acute inflammation—seems to have been nearly forgotten about.

The thing is, acute inflammation—the kind that happens when you stub your toe—is a normal and healthy function of the immune system. It’s necessary to fight off or heal from infection, injury, and illness. That redness, swelling, and tenderness you see when you sprain your ankle, or the runny nose and cough you notice when you catch a cold, are just signs that your body is taking appropriate measures to protect and heal itself.

Interestingly, it turns out that acute inflammation is necessary for another important process in the body: strength building and muscle growth.

The Case for Inflammation and Muscle Growth

 2017 study published in the peer-reviewed journal Acta Physiologica showed that anti-inflammatory drugs block muscle growth, at least in young healthy individuals.

In the 8-week long study, 31 men and women between the ages of 18 and 35 were given daily doses of either:

  • 75 milligrams of acetylsalicylic acid (a low dose of aspirin), or
  • 1,200 milligrams of ibuprofen (the maximum recommended dose for a 24-hour period)

During this time, the subjects also participated in a supervised strength training program for the quadriceps muscles two to three times per week. At the end of 8 weeks, people in the high dose NSAID group had thigh muscle volumes two times smaller than the people in the low dose group. The high dose NSAID group also had lower muscle strength.

The authors concluded: “[Y]oung individuals using resistance training to maximize muscle growth or strength should avoid excessive intake of anti‐inflammatory drugs.”

So what’s going on?

When you train hard enough, your muscle fibers actually become damaged, at least at the microscopic level. It’s not injury—it’s acute inflammation. This is a normal training effect that triggers the repair and rebuilding process muscles need to get stronger. The process is mediated by a whole bunch of molecules working in harmony to heal and grow muscle fibers, including cytokines, macrophages, COX enzymes, prostaglandin, and growth hormones.

Importantly, this repair and rebuilding process would never happen without the acute inflammation brought on by exercise! Conversely, chronic inflammation can hinder strengthening because (among other things) it releases proteins that prevent muscle growth and promote muscle tissue breakdown.

In short, acute inflammation is healthy and essential for many processes in the body, including muscle growth. Meanwhile, chronic inflammation is really as bad as everyone says it is.

How to Optimize the Exercise-Induced Inflammatory Process That Drives Muscle Growth

To be very clear about something—this article was not written by your doctor. You should always chat with yours before you start or stop any medications.

That said, if you want to maximize your strength training sessions, consider the following tips:

  • Don’t suppress the normal acute inflammatory process that occurs after a tough gym session. That means: avoid taking ibuprofen or other NSAIDs, and avoid using ice to soothe a sore muscle. Both of these at-home remedies, especially if done regularly, can block the training-induced inflammation your muscles need to grow stronger and bigger.
  • Be sure that you’re consuming plenty of healthy foods that will help you avoid the muscle-damaging effects of chronic inflammation. This includes curcumin (a compound found in the spice turmeric), antioxidant-rich berries and leafy green veggies, and healthy fats (such as those found in macadamia nuts and almonds). You can research which nuts are healthiest, which are best for your diet, or have a more desirable macronutrient makeup to determine which to add to your snacks and meals.
  • Avoid other lifestyle behaviors that promote chronic inflammation, including smoking, excessive alcohol consumption, lack of sleep, high stress—and over-training.

Lastly, schedule a few rest days or active recovery days into your weekly workout routine. This helps you prevent over-training and avoid true injury. Easy activities like stretching, swimming, hiking, and yoga allow your muscles to run through the repair and recovery process and come out stronger on the other side. Plus, adequate rest allows you to train with intensity during your next session…so you can kickstart the acute inflammation effect all over again.


1- Article in Acta Physiologica (
2- Prostaglandin E2 and muscle stem-cell function article in Proceedings of the National Academy of Sciences (


Licensed Physical Therapist

Sara McEvoy, PT, DPT, is a licensed and board certified physical therapist. She earned her doctoral degree from Boston University. Sara is also a professional freelance writer and copywriter creating content almost exclusively within the health and wellness field.

When Sara is not writing or in clinical practice, she enjoys reading, exercising, and volunteering at her local Humane Society

Twitter: @SaraMcEvoy

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