Dark side of running: Does it cause osteoarthritis?

Whether you are a morning runner or like to enjoy the evening breeze, if running is one of the great joys of your day, it hardly ever fails to cheer you up. The joy of running apart, it is a great form of exercise. It can help burn those extra calories and even strengthen your muscles. It can help your heart and its associated vessels — what doctors call your cardiovascular health. And it can help boost your self-image and body confidence. But there are a few things you also need to know.

A potential killjoy and one that puts off many individuals from running is the possibility of injuries at the moment or later in life. Indeed, many runners get injured doing their favorite activity. But is there any credit to the belief that running long distances could also cause osteoarthritis? Before we explore that, let’s see what osteoarthritis is.

What is osteoarthritis?

At each end of the bones in our joints, there is a rubbery collagen tissue called articular cartilage. Its function is to absorb shock, distribute stress equally, and avoid friction between the bones during movement. When we run, the ground sends up a huge force that reaches our knee and hip joints. The cartilage makes sure the two ends of both the knee and hip joints move smoothly and in alignment with each other. But because of increasing stress over the years or because of overuse, the cartilage becomes stiff and loses its rubbery quality. Eventually, it begins to wear out and affects even the layer of bone beneath it (subchondral bone).

To make up for the cartilage loss, the body starts over-producing bones, and these bony projections, called osteophytes, enter the joint space. This condition is known as osteoarthritis, and it causes pain, swelling, and stiffness and makes movement difficult.

Since everyday activities involve a lot of use of these joints, osteoarthritis is an extremely common condition, though it does not always show symptoms. In an X-ray or an MRI scan, approximately 80 percent of the population would likely show bone degradation in the joints by the age of 65. But, of them, only 60 percent would show any symptom.

Does running long distance cause osteoarthritis?

Common sense would tell us that since long-distance running puts a lot of stress on our knee and hip joints, runners would be at a great risk of osteoarthritis. While most early studies showed mixed results with regard to relating osteoarthritis directly to long-distance running, recent researches have sought to debunk it as a myth.

Most studies now say no

A 1985 study compared 504 former cross-country runners with 287 former swimmers and followed this up over an average period of 25 years. It showed that only 0.8 percent of the runners required surgery to cure osteoarthritis as opposed to the 2.1 percent swimmers who needed surgery to relieve them of pain.

The study concluded that neither the distance of a run nor the number of years of running was related to osteoarthritis.

A 1993 study showed that there was no difference in the incidence of osteoarthritis in runners and non-runners in the five years that they were monitored as part of the study. Rather, it attributed age as a factor.

A recent 2006 research claims that animal studies show that osteoarthritis is more common when there’s a history of injury. Human studies show evidence of osteoarthritis in endurance athletes, which would include long-distance runners, but there is no increase in symptoms. On the contrary, long-distance running may even have a protective function against joint wear and tear.

Though earlier studies did say yes

In a study first conducted in 1973 and then followed up in 1988, researchers tested long-distance runners and untrained men of similar age. They found that those who ran long distance (i.e., 97 km per week) showed the highest evidence of osteoarthritis of the hip, and among them, those who ran faster had more bone degradation. Another study in 1996 found that women who were former elite long-distance runners and tennis players had a twofold to threefold increase in the incidence of osteoarthritis. When examined under X-rays or other radiographic scans, they showed more joint narrowing in the hip joint and the knee joints between the thigh bone, the kneecap, and the shin bone and many more osteophytes.

The problem with these studies was that the sample size wasn’t big enough in the first one and it focused only on men. And in the second one, though the study was quite representative of the ratio of runners (81) to the general population who did not participate in running (977), it focused only on women. Neither study took into account the injuries the participants had, which could have contributed to the degeneration of their joints.

Why is running actually good?

As we walk or run, the ground sends back a strong impact, which we refer to as load. It would seem natural that running would produce more load and more chances of wear and tear. But one reason this isn’t usually the case is: the length of the stride and the little duration of the ground contact we have while running lowers the load per unit distance. This means that there is no sudden peaking of stress in the knee as it is uniformly distributed.

Muscle weakness, especially in the thigh muscles in women, caused by lack of physical activity has been found to be a risk factor of osteoarthritis.

But by making the joints stay active and function well and by strengthening the muscles and tissues, running actually staves off stiffness of joints and bone degeneration. Regular running also strengthens the cartilage and keeps them elastic.

Since running also reduces weight, the longer we run the lesser are our risks of osteoarthritis. In fact, running more than 1.2 miles a day may reduce our risk of osteoarthritis by 15 percent. Because women’s chances of getting osteoarthritis increase after their menopause because of the low levels of estrogen that make their bones brittle, women runners nearer that age may need to supplement their diets well.

Running with these risk factors may cause osteoarthritis

While there has been no conclusive evidence, high-speed running, over a long period of time may increase the risk of osteoarthritis. Other risk factors include: aging, bad form while running, overuse of the joints — especially when they are already injured — a history of injuries, increased body mass, obesity, and a family history of osteoarthritis.

As a precaution though, runners should run moderate distances in moderate speeds, maintain the right form, take rest, get proper nutrition, and ALWAYS do the appropriate warm-ups and stretches to enjoy the positive effects of running, without fearing osteoarthritis.