Synovial Fluid and Inflamed Joints

Yoga can help this important body fluid keep your joints at their strong and supple best.

By Julie Gudmestad

When my students are feeling warm and good and happy after a class, I jokingly ask if they feel like they've just had a tune-up and oil change. In fact, while yoga doesn't change any fluids, it does do a wonderful job of moving fluids around in your body. Your blood circulates in your arteries and veins, and your lymph flows through the spaces around all your cells; both fluids can be cleansed of metabolic by-products and your blood replenished with oxygen and nutrients. Yoga also helps circulate the synovial fluid inside your joints, but—contrary to common perception—it doesn't warm up or stimulate the manufacture of this important substance.

So what is synovial fluid? And if yoga helps move it around, what effect does that have on your health and mobility?

Understanding Synovial Fluid

Synovial fluid is the slippery fluid that fills most of the body's joints. All joints occur where two separate bones intersect or overlap, but there are a few that don't contain synovial fluid and have very limited movement, including the intervertebral (between the vertebrae) discs and the two sacroiliac joints on the back of the pelvis. The rest are synovial joints, which are freely movable and need a system that cushions the ends of the bones, allowing them to glide over each other without friction. This system consists of hyaline cartilage, the smooth, whitish covering on the ends of the bones, and the synovial fluid, which fills the space between the cartilage surfaces and facilitates smooth, painless movement between bones. This clear, slightly viscous fluid is also important because it delivers nutrients and oxygen to the hyaline cartilage, which—unlike most body tissues—doesn't have its own blood supply. Any joint movement helps circulate the synovial fluid, which feeds the cartilage; practicing yoga poses therefore helps keep the cartilage well nourished.

Each synovial joint has a fibrous capsule surrounding the joint, which helps hold the bones together, along with the ligaments (which join bone to bone) and tendons (which join muscle to bone). The joint capsule is lined by the synovial membrane, which manufactures the synovial fluid. Your body automatically produces the necessary amount of this lubricating fluid. Although the idea that yoga stimulates production of synovial fluid creates a lovely image, there actually isn't any time when the well runs dry.

Inflammation: When Too Much Is Too Much

In fact, the only problem with the amount of fluid occurs when there is too much. This problem is part of the inflammatory process, which is defined by the presence of swelling, pain, redness, and heat. Inflammation is the body's response to injury, as well as part of the process of arthritis, which includes the wearing away of hyaline cartilage. (In more advanced cases of osteoarthritis—the wear-and-tear arthritis commonly associated with old age—and in rheumatoid arthritis—the autoimmune disease in which the body attacks its own joint tissues—the synovial membrane also becomes painfully inflamed, and the cartilage can wear away until bone rests painfully on bone.)

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