Running is one of the most widely performed types of exercise throughout the world. It’s easy to do, doesn’t require a ton of expensive equipment, and can easily be done in most environments. On top of this, people who run enjoy a number of benefits from this form of exercise, including improved cardiovascular fitness, stress relief, and aid in/maintenance of weight loss.
However, many people who run are told by friends, family, and sometimes even healthcare providers that running is actually bad for them, specifically when it comes to knee health. Many people believe that running will increase your risk of knee arthritis due to the constant pounding and impact that your knees endure during this type of exercise. The question is, is this true?
In general, this thought has luckily been found out to not be true! In fact, there are several studies that have looked to answer this question, and have come out with some potentially surprising results!
This study is a meta-analysis and systematic review that analyzed 25 different studies on this topic. What they found was that approximately 3.5% of recreational runners (ie not professional runners or elite-level runners who compete at the international level) had knee arthritis, while 10.2% of non-runners had knee arthritis. However, they found that approximately 13.3% of competitive runners had knee arthritis, which is slightly higher than non-runners.
The fact that the elite-level competitive runners had slightly higher rates of knee arthritis than non-runners, but significantly higher rates than the recreational runners is most likely due to the amount of training that they performed, and not the act of running itself. Elite-level athletes by definition utilize much higher training volumes and intensities, which increases injury risk no matter the activity.
In fact, the differences in knee arthritis risk between the different types of people (competitive runners, recreational runners, non-runners) showed that recreational running can actually help keep your knees healthy! A likely reason for why this is the case is that our knees are synovial joints that have cartilage on the ends of the bones that are bathed in synovial fluid. This synovial fluid helps to nourish the cartilage and keep it healthy, and is stimulated by loading of the joint, which happens during running (as well as resistance training)!
So all in all, running is not bad for you nor your knees, you just simply need to run with appropriate weekly mileages and intensities for your fitness level and goals!