By YouBeauty editors


The Scientist: John Indalecio, a hand therapist at the Hospital for Special Surgery in New York


The Answer: There is no compelling scientific evidence that cracking your knuckles causes arthritis. But a long-standing habit could affect joint function down the road. Here’s what’s going on.


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A joint is the point at which two (or more) bones meet. Ligaments connect the bones to one another, and a joint capsule surrounds the whole thing. It is filled with a natural lubricant called synovial fluid that helps the joint move smoothly. When you make the motion to crack your knuckles, the joint is pulled apart, expanding the capsule. This decreases the pressure inside the capsule, forcing gasses dissolved in the synovial fluid to release into the space to equalize it. That rush of gas causes the pop! sound -- so satisfying to you, so annoying to everyone else in the room. It's like popping the top on a can of soda.


It takes about 30 minutes for the carbon dioxide, nitrogen and oxygen to dissolve back into the synovial fluid. That's why you have to wait a while before you can get a second pop.


Cracking your knuckles feels good because it stretches the joint and stimulates the nerve endings found there. Can it be dangerous? Well, while it's unlikely that knuckle cracking can do the cartilage damage that leads to arthritis, it can lead to instability in the joint and loss of grip strength and hand function.



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    A recent animal study conducted by Wake Forest University researchers showed that <a href="http://www.huffingtonpost.com/2013/01/28/stress-prostate-cancer-mice_n_2569256.html?1359412688">stress could help cancer cells survive</a> against anti-cancer drugs. The study, published in the Journal of Clinical Investigation, was done on mice induced to experience stress by being exposed to the scent of a predator. When experiencing this stress, an anti-cancer drug administered to the mice was <a href="http://www.huffingtonpost.com/2013/01/28/stress-prostate-cancer-mice_n_2569256.html?1359412688">less effective at killing cancer cells</a>, and the cancer cells were actually <em>kept</em> from dying because of the adrenaline produced by the mice, Everyday Health reported.




  • Shrinks The Brain


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  • Prematurely Ages Kids


    The extreme duress that a child experiences when exposed to violence early on could lead to <a href="http://healthland.time.com/2012/04/24/how-bullying-and-abuse-may-age-children-prematurely/">premature aging of his or her cells</a>, according to research in the journal Molecular Psychiatry. The study, which followed 236 children born in England and Wales between the ages of 5 and 10, showed that those who had been bullied, as well as those who were witnesses of violent acts or victims of violence by an adult, had shorter telomeres -- a sign that they <a href="http://healthland.time.com/2012/04/24/how-bullying-and-abuse-may-age-children-prematurely/">were aging faster</a>, TIME reported.




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