Scientists from Brigham Young University in the USA found that pro-inflammatory molecules actually go down in the knee joint after running.
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They measured inflammation markers in extracted synovial fluid from the knee joint of several healthy men and women, aged 18-35, both before and after running. The results showed these markers, two cytokines named GM-CSF and IL-15, decreased in concentration in the subjects after 30 minutes of running. When the same fluids were extracted before and after a non-running condition, the inflammation markers stayed at similar levels.
"It flies in the face of intuition," said study co author Matt Seeley, associate professor of exercise science at BYU. "This idea that long-distance running is bad for your knees might be a myth."
"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.
Hyldahl said the study results indicate running is chondroprotective, which means exercise may help delay the onset of joint degenerative diseases such as osteoarthritis.
This is potentially great news, since osteoarthritis - the painful disease where cartilage at the end of bones wears down and gradually worsens over time -- affects about 27 million people in the United States.
"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."
The study was published in the European Journal of Applied Physiology
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