Running Actually Lowers Inflammation in Knees

Running is known to help build strong bones, strengthen muscles and maintain a healthy weight. But at the same time is criticized for causing inflammation and soreness, and taking its toll on the cartilage in the knee joint.

A new study out of Brigham Young University (BYU), however, finds that running can actually do the opposite. Instead of increasing, running actually reduces inflammation, and it as well goes down in knee joints after running.

“It flies in the face of intuition,” said study coauthor Matt Seeley, who is associate professor of exercise science at BYU. “This idea that long-distance running is bad for your knees might be a myth.”

In the small study, Seeley and his team of BYU colleagues, as well as Dr. Eric Robinson from Intermountain Healthcare, took synovial fluid- a thick, stringy fluid found in the cavities of synovial joint- from the knee joints of six healthy people (both male and female) between the ages of 18-35, both before and after running.

They measured two inflammation markers in the knee joint fluid, namely GM-CSF and IL-15, which are cytokines – the signalling proteins secreted by certain cells. Unlike their anti-inflammatory causing peers, these two cytokines cause inflammation in the body.

The researchers found that the levels of both GM-CSF and IL-15 in the extracted synovial fluid decreased in concentration in the study participants after 30 minutes of running, indicating that the inflammatory response was actually reduced.

When the synovial fluids were extracted before and after a non-running condition, no change in the levels of the inflammation markers was observed.

“What we now know is that for young, healthy individuals, exercise creates an anti-inflammatory environment that may be beneficial in terms of long-term joint health,” said study lead author Robert Hyldahl, BYU assistant professor of exercise science.

In addition, the study revealed that rather than contributing to arthritis, running can be considered “chondroprotective,” which means it prevents joint-space narrowing and delays the onset of painful and degenerative joint diseases such as osteoarthritis.

“This study does not indicate that distance runners are any more likely to get osteoarthritis than any other person,” Seeley said. “Instead, this study suggests exercise can be a type of medicine.”

Hyldahl and colleagues now planning to expand their research to subjects living with knee injuries. They’re specifically looking to do similar tests on individuals who have suffered anterior cruciate ligament (ACL) injuries, which is the tearing of one of the major ligaments in the knee.

The study was recently published in the European Journal of Applied Physiology.