Bringing together modern science and Ayurveda, we now have the tools to clarify an old question about the cracking of knuckles: Why does it make that sound and why do joints crack more with age?1
The crack apparently comes from a bubble forming in the fluid within the joint when the bones separate, according to a recent study2. It’s like a tiny air bag inflating. Theses findings confirm the original theory about knuckle-cracking, which was first proposed in 1947 but challenged in the 1970s.
In Ayurveda (the traditional Indian school of medicine), the formation of gas bubbles in the joint is emphasized as a cause of popping sounds. With the prevalence of the Vata Dosha (the two elements space and air in the constitution of the body) extra gases are secreted into the synovial fluids, so there is more and more of the cracking and popping sounds. Cracking joints aren’t a symptom of old age… it is only that Vata increases with age and influences the constituents of synovial fluid.4