• Your muscles ache when you have the flu because the virus is wreaking havoc on your body and causing inflammation.
  • Muscle aches should resolve when the virus clears your body. Some people may recover from the flu in a few days and others within two weeks.
  • While mild aches associated with the flu shouldn’t be a cause for concern, there is a small risk it could develop into something more serious called myositis.
  • This article was reviewed by Graham Snyder, MD, MS, who is the medical director for the Infection Prevention and Hospital Epidemiology branch at the University of Pittsburgh Medical Center.
  • Visit Insider’s homepage for more stories.

If you have the flu, you’re probably spending more time in bed than usual. So then why do your muscles seem to ache all over if you haven’t been using them very much?

Turns out, those muscle aches aren’t that different from the soreness you may feel after an intense workout. That’s because the pain in both cases is the result of inflammation.

In the case of muscle aches when you’re sick with the flu, the inflammation is caused by the flu virus wreaking havoc on your cells.

“Viruses are essentially little genetic data bombs, made of either RNA or DNA,” says Emily Cardwell, a registered nurse with Show Me Your Stethoscope. “They cannot replicate on their own and so require a host to do the work for them. Cells that are infected may die as part of the immune response and leave inflammation as a byproduct.”

As with other symptoms associated with the flu, muscle aches should resolve when the virus clears your body. Some people may recover in a few days and others within two weeks.

How to ease muscle aches

You can do a few things to alleviate the symptoms and prevent further inflammation. Cardwell recommends resting, avoiding exercise, and following the advice of your medical provider regarding anti-inflammatories, which could help reduce the pain.

Heat can help too. "Heat may help as it increases blood flow to the tissue and allows for improved oxygenation, removal of inflammatory byproducts, and relaxation," Cardwell says.

While mild aches associated with the flu shouldn't be a cause for concern, there is a small risk it could develop into something more serious.

"Myositis is a more serious condition that results in muscle-cell inflammation and necrosis, a medical complication of the flu," Cardwell adds. "But myositis occurs only in a small percent of those affected with influenza and is most common in children."

If you're experiencing severe pain, weakness, and swelling, seek a medical provider.