Who among us has not at least once in his life crunched the joints, for example, on his fingers? For some people it has already become a habit, while others are afraid to repeat it - because there are rumors that after such actions you can get arthritis. Is this true?
Actually, no. If only because the joints do not take part in the "joint crunch"! Surprisingly, the characteristic crackle is created by air bubbles bursting in the fluid.
We are talking about synovial fluid - this thick substance fills the cavities of the joints, acting as a lubricant. Synovial fluid has been found to contain large amounts of dissolved carbon dioxide. During sharp movement, gas bubbles form in the cavities between the joints - recall the physical process of cavitation - and it is the moment of formation of hundreds of such bubbles that is characterized by a specific crunching sound. Already 0.01 second after occurrence, most of the bubbles silently recede. The rest continue to dissolve in the liquid for about 15 minutes: this explains the fact that we cannot "crunch the joints" twice in a row in a short period of time.
Since no stress is found on the joints in such actions, these actions can in no way lead to arthritis. This is proven not only by numerous medical studies conducted specifically to debunk this myth, but also by the experience of Professor Donald Unger, who crunched the joints of one hand every day for 50 years, but never crunched the joints of the other. After 50 years, a study showed that daily joint crunching had no effect on his health, and Donald Unger himself was awarded the Schnobel Prize for his research