In younger individuals, inflammation markers actually decrease in the knee joint after running, and running thus may help delay the onset of joint degenerative diseases, found a Brigham Young University study.
"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."
In a recent study, Seeley and a group of BYU colleagues, as well as Dr Eric Robinson from Intermountain Healthcare, measured inflammation markers in the knee joint fluid of several healthy men and women aged 18-35, both before and after running.
The researchers found that the specific markers they were looking for in the extracted synovial fluid – 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.
"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 27m people in the US.
"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."
Researchers, which included then undergraduate (and now grad student) Alyssa Evans and PhD student Sunku Kwon, now plan to turn their attention to study subjects with previous knee injuries. Specifically, they're looking to do similar tests on people who have suffered ACL injuries.
Abstract
Introduction: Regular exercise protects against degenerative joint disorders, yet the mechanisms that underlie these benefits are poorly understood. Chronic, low-grade inflammation is widely implicated in the onset and progression of degenerative joint disease.
Purpose: To examine the effect of running on knee intra-articular and circulating markers of inflammation and cartilage turnover in healthy men and women.
Methods: Six recreational runners completed a running (30 min) and control (unloaded for 30 min) session in a counterbalanced order. Synovial fluid (SF) and serum samples were taken before and after each session. Cytokine concentration was measured in SF and serum using a multiplexed cytokine magnetic bead array. Ground reaction forces were measured during the run.
Results: There were no changes in serum or SF cytokine concentration in the control condition. The cytokine GM-CSF decreased from 10.7 ± 9.8 to 6.2 ± 5.9 pg/ml pre- to post-run (p = 0.03). IL-15 showed a trend for decreasing concentration pre- (6.7 ± 7.5 pg/ml) to post-run (4.3 ± 2.7 pg/ml) (p = 0.06). Changes in IL-15 concentration negatively correlated with the mean number of foot strikes during the run (r2 = 0.67; p = 0.047). The control condition induced a decrease in serum COMP and an increase in SF COMP, while conversely the run induced an increase in serum COMP and a decrease in SF COMP. Changes in serum and SF COMP pre- to post-intervention were inversely correlated (r2 = 0.47; p = 0.01).
Conclusions: Running appears to decrease knee intra-articular pro-inflammatory cytokine concentration and facilitates the movement of COMP from the joint space to the serum.
Authors
Robert D Hyldahl, Alyssa Evans, Sunku Kwon, Sarah T Ridge, Eric Robinson, J Ty Hopkins, Matthew K Seeley
[link url="https://www.sciencedaily.com/releases/2016/12/161209100236.htm"]Brigham Young University material[/link]
[link url="http://link.springer.com/article/10.1007%2Fs00421-016-3474-z"]European Journal of Applied Physiology abstract[/link]