A common question we hear is people wondering if running is bad for their joints. It would seem to make sense that the forces from hitting the pavement could be hard on our joints. Interestingly enough, researchers decided to take a look at the relationship between running and development of arthritis, and the results were surprising.
First off, a little background on the study. They divided the study participants into three groups: 1) Recreational runners; 2) Sedentary individuals (non-runners); 3) Competitive runners and looked at the prevalence of knee and/or hip arthritis within each group. Competitive runners were professional, elite or ex-elite athletes, so basically people making money to run and Olympians. The results showed that recreational running had the lowest rates of developing arthritis at 3.5%. It’s not too surprising that the competitive runner group showed the highest rate at 13.3% because of the high intensity of running. What was surprising is the sedentary group also had a double digit rate of 10.2%. So the take away from this study is that recreational levels of running can not only help your overall health, but prevent cumulative stress as we age.
These results might seem surprising considering the people who did not run had a higher rate of arthritis but were not having the same physical stresses. To answer that we can look a little bit at how we treat plants. Warmer weather doesn’t only mean more people out on the trails but it also means more people in their gardens and we can see some similarities in how plants and the human body respond to physical stresses. Whether you are buying your plants from a nursery or you have nurtured your very own plant babies in your home, these plants have to go through a process called “hardening”. If you took a plant that had spent its entire life in the calm, relaxing atmosphere of your home (unless you have a young children) and plopped it in the ground it would have a very tough time surviving. That’s because the plant has adapted to the needs of its environment and in the house it doesn’t have to put up with changes in wind or temperature and has filtered UV rays from your windows. So these newly grown plants are slowly exposed to the elements for a few hours at a time to allow them to toughen up, or “harden”. Over the course of a week they become ready for the earth or pots to do their photosynthesizing and growing. This is because the plant responds to the stresses by making the stem stronger to tolerate the winds and by toughening to the exposure to increased sun rays.
This brings us back to the study on running. Our bodies respond a lot the same way as plants when exposed to physical stresses like running…we toughen up or harden our tissues. This is why the sedentary group had a higher rate of arthritis; their tissues were not as tough because they were not exposed to the physical stresses to make them harden. There is a tipping point with the stresses where too much can lead to increased rates and that is shown with the competitive group. But in all honestly most of us are not competing except for a few races here or there and that should be just enough to make our tissues stronger in so many healthy ways. We see this same toughening response with our bones. One of the recommended treatments for osteopenia or osteoporosis (weakening of bones which can lead to increased risk of fractures) is weight bearing exercise/activity. This is because the body responds to the stresses of our body weight through our bones by making the bones stronger.
The lesson we can take away from this is that if running is your thing, then keep at it because it has all sorts of health benefits, and just like we slowly expose the plant babies to the elements, make sure you are increasing your training in a smart way. If running is not your thing then don’t feel like you need to start. This process of tissue hardening applies to all types of exercise in different ways and the main concept is to stay active with things you enjoy.
The Association of Recreational and Competitive Running With Hip and Knee Osteoarthritis: A Systematic Review and Meta-analysis” (J Orthop Sports Phys Ther 2017;47(6):373–390. doi:10.2519/jospt.2017.7137