THURSDAY, Jan. 5, 2017 -- Everybody believes running can leave you sore and swollen, right? Well, a new study suggests running might actually reduce inflammation in joints. 
 
 "It flies in the face of intuition," said study co-author Matt Seeley, an associate professor of exercise sciences at Brigham Young University in Provo, Utah. "This idea that long-distance running is bad for your knees might be a myth." 
 
 Seeley and his colleagues reached their surprising conclusion after analyzing the knee joint fluid of several healthy men and women between the ages of 18 and 35. The researchers looked for signs of inflammation in chemical markers before and after a 30-minute run and found little difference. 
 
 "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," lead author Robert Hyldahl said in a university news release. Hyldahl is an assistant professor of exercise science at BYU. 
 
 The researchers said the study suggests running could actually delay development of degenerative joint diseases like 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." 
 
 The study was published recently in the European Journal of Applied Physiology. 
 
 For more about knee pain, try the Arthritis Foundation. 
 
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 ||||| 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 (r 2 = 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 (r 2 = 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. ||||| But other researchers have wondered whether running might have a more direct impact on knee joints, perhaps by altering the working of various cells inside the knee. 
 
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 To find out, researchers at Brigham Young University in Provo, Utah, recruited 15 male and female runners under the age of 30 with no history of knee injury or arthritis. The scientists wished to study people with healthy knees in order to better isolate running’s effects on otherwise normal joints. 
 
 These volunteers visited a clinic where they had blood drawn from an arm. The researchers also siphoned off a small amount of synovial fluid, a lubricating fluid that reduces friction inside joints, from their right knee. Healthy knees contain only a soupçon of the stuff; arthritic and otherwise unhealthy knees tend to contain much more. 
 
 The volunteers next were delivered, in wheelchairs, to the university’s nearby biomechanics lab. There, they either sat quietly for 30 minutes or ran on a treadmill for the same 30 minutes at their preferred running pace. 
 
 After either running or sitting, they again were wheeled to the clinic and the blood and synovial fluid draws were repeated. 
 
 Each volunteer completed both a sitting and running session on separate days. 
 
 Then the researchers looked for a variety of substances in the young people’s blood and synovial fluid. 
 
 In particular, they focused on molecules that are associated with inflammation. Low-grade inflammation in the knee has been shown to contribute to the development and progression of arthritis. 
 
 So the researchers looked for changes in the levels of several types of cells that are known to either increase or blunt the amount of inflammation inside the knee. 
 
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 They also looked at changes in the levels of another substance unpoetically known as cartilage oligomeric matrix protein, or COMP. This substance tends to accumulate in diseased knees and is often used as a marker of incipient or worsening arthritis. People with arthritis can have about five times as much COMP in their synovial fluid as do people with healthy knees. 
 
 Unfortunately, because it had turned out to be technically difficult to safely extract much synovial fluid from these healthy knees, the scientists wound up with complete numbers from only six of the runners. 
 
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 But the data were interesting and consistent. In almost every case, the runners’ knees showed substantially lower levels of two types of cells that can contribute to inflammation within the synovial fluid, compared to their baseline levels. 
 
 The runners also showed a shift in their COMP levels. After the run, they displayed more of the substance in their blood and less in their synovial fluid. In effect, running seemed to have squeezed the molecules out of the knee and into the blood. 
 
 Meanwhile, sitting had slightly increased levels of COMP inside people’s knees, and also raised the concentration of one of the inflammatory molecules. 
 
 These findings suggest that a single half-hour session of running changes the interior of the knee, reducing inflammation and lessening levels of a marker of arthritis, says Robert Hyldahl, a professor of exercise science at B.Y.U. and lead author of the study, published in the European Journal of Applied Physiology. 
 
 But sitting for 30 minutes also changed the knee, he points out, which he and his colleagues had not expected. Sitting seemed to make the knee biochemically more vulnerable to later disease. 
 
 Dr. Hyldahl noted that this was a very small and short-term study. He and his colleagues would like to repeat it with much larger numbers, “once we figure out how to get more synovial fluid” safely from healthy knees, he says. 
 
 They also hope to study longer running distances and different paces, to see how those variables affect changes within the knee, and to recruit older and injured runners, whose knees might have begun to respond fundamentally differently to the activity than the joints of healthy people in their 20s. 
 
 But even with these limitations, the findings suggest that moderate amounts of running are “not likely to harm healthy knees and probably offer protection” against joint damage, Dr. Hyldahl says.
– "It flies in the face of intuition," Matt Seeley tells UPI. Seeley is the co-author of a study published in the European Journal of Applied Physiology that may upend what we thought we knew about running's effect on knees. Conventional wisdom says running is hard on the knee joints, deteriorating cartilage and causing arthritis, the New York Times reports. While recent studies have shown that runners tend to be less likely to develop arthritis in the knees as they age, scientists have largely chalked that up to the fact that runners also tend to weigh less than the rest of the population. But the new study out of Brigham Young University gives evidence that running may actually change the biochemistry of the knee to protect against inflammation and arthritis. In an admittedly small study of six runners, researchers looked at proteins and cells in knee fluid associated with inflammation after 30 minutes of running, sitting, or non-knee-intensive exercise, Canadian Running Magazine reports. They found that just half an hour of running was enough to reduce the risk factors of inflammation in knees. On the flip side, sitting around for half an hour increased risk factors for inflammation. (Non-knee-intensive exercise—elliptical, cycling, etc.—had no effect.) It also appears that the longer a person runs, the less risk they're at for inflammation of the knees. (Too busy for daily workouts? Study says that's OK.)