• Human Body

What Happens When You Crack Your Knuckles?

Maybe you've heard the words, "Don't crack your knuckles - you're going to give yourself arthritis!" Maybe it made you immediately stop in your tracks, or perhaps you just rolled your eyes but secretly wondered if your admonisher was right. Well, wonder no more - if you were in the latter category, you're in the clear. There has never been a case of arthritis found to be caused by knuckle cracking, even if you do it frequently.

But have you ever wondered what happens when you pop your knuckles? Bone isn't grinding on bone like many have thought - your knuckle actually cracks as a result of changing pressure in the fluid that lubricates the joints. The fluid has a thick, honey-like texture, and scientists still aren't sure if the popping noise means that a bubble is being formed in the fluid or if a bubble is literally being popped. Read on to discover the studies that have been done on this fascinating topic, and don't forget to send this to your mom if she always told you to quit cracking your knuckles!

  • No, it doesn't lead to arthritis... but it's probably best to crack in moderation.

    If you had a parental or authority figure get mad at you for popping your knuckles because "it could cause arthritis," they were probably just trying to be helpful - but there's zero evidence to support the belief that cracking your knuckles leads to arthritis. Yes, you read that right - zero evidence. It's basically an old wive's tale. So crack away! Just don't go too overboard - long-term effects of overzealous cracking have yet to be concretely determined.

    And those who pop frequently, according to Harvard Health, "were more likely to have swollen hands and reduced grip strength. And there are at least two published reports of injuries suffered while people were trying to crack their knuckles." So you're probably in the clear for long-term health effects, but moderation is best to be on the safe side.

  • Cracking too frequently can lead to inflammation.

    Anything involving moving tendons (which cracking your knuckles does) can cause inflammation if done frequently. And, according to a research study by Jorge Castellanos and David Axelrod called "Effect of habitual knuckle cracking on hand function," "Habitual knuckle cracking was associated with manual labour, biting of the nails, smoking, and drinking alcohol. It is concluded that habitual knuckle cracking results in functional hand impairment."

    So you're good to crack on - again, just try not to overdo it!

  • A doctor experimented on himself to determine the long-term effects of knuckle cracking.

    Dr. Donald Unger performed his own unique experiment to determine if knuckle cracking was harmful - and used his own body as a guinea pig. His study, “Does Knuckle Cracking Lead to Arthritis of the Fingers?," was published in the journal Arthritis & Rheumatism in 1998.

    From his publication: “For 50 years, the author cracked the knuckles of his left hand at least twice a day, leaving those on the right as a control. Thus, the knuckles on the left were cracked at least 36,500 times, while those on the right cracked rarely and spontaneously.”

    The results? No difference. “There was no arthritis in either hand, and no apparent differences between the two hands.” Unger concluded: “there is no apparent relationship between knuckle cracking and the subsequent development of arthritis of the fingers.”

    While this experiment was only performed on one man, the results were interesting enough to spawn other studies, again finding the same results.