Osteoarthritis is a painful disease of wear-and-tear as the cushioning in the joints wears down over time. Some activities—particularly those that lead to injuries—can increase your risk of osteo. But running, as demanding as it is on knees and other joints, actually helps prevent osteoarthritis, according to a new study.
Researchers at UC Berkley followed about 75,000 runners and 15,000 walkers over a seven-year period. During that time, about 2,000 runners (or 2.67%) developed osteoarthritis and about 260 had hip replacements. The walkers had just fewer than 700 cases (or 4.67%) of osteoarthritis and about 115 hip replacements. In simpler words, the researchers found that running was better for joint health than walking.
Runners who put in 8-15 miles a week benefitted the most, though more agressive runners (up to 30 miles a week) also had better joint health and reaped other health benefits.
There are two main reasons given for why running is an effective preventer of osteoarthritis: 1) Runners tend to be in better shape than the average person, gaining less weight as they age; 2) Running triggers joints to develop more cartilage.
The study's conclusion pondered a connection between BMI (body mass index) and osteroarthritis. Being overweight or obese increases the risk of developing osteo because more weight puts more pressure on the joints, especially the knees. Other risk factors include old age and working in a field that requires repetitive tasks (factory work, for example).
Running, on the other hand, strengthens knees and other joints by putting extra pressure (albeit, a more dynamic pressure) on them, and the body responds by building up the joints with cartilage. That extra cartilage provides longer-term cushioning and wears less easily, helping stave off—or altogether prevent—osteoarthritis.