“Doesn’t that hurt?” “It will give you arthritis!” “That’s the most bone-chilling sound in the world.”
I’ve heard it all. And I know, my knuckle-cracking habit isn’t exactly flattering. But I can’t help it. I’ve been popping my fingers, back, neck, and other appendages for years. I don’t even remember when I first started. Primary school? By now, cracking my knuckles is as deeply embedded in my lifestyle as applying lip balm when my pucker feels dry or eating when I’m hungry. (I even force my boyfriend to crack my back for me sometimes—a textbook case of codependence.)
Sure, I’ve gone through sober periods where I’ve put my habit on hold. But mostly, cracking my knuckles feels as necessary as scratching a needling, torturous itch. (Cue sarcastic jokes about being addicted to “crack.”)
That said, I don’t want to be the gross girl who pops her knuckles all day at work. Even I’ll admit that the noise is disturbingly loud for such a small action. Plus, I’m sick of hearing people tell me I’m damaging my joints. Cracking my knuckles isn’t actually harming me, right? Actually, while we’re asking questions, what is knuckle cracking, anyway?
To find out once and for all, I spoke to San Diego–based chiropractor Dr. Ryan Curda, D.C., as well as New York City–based physical therapist Dr. Scott Weiss, D.P.T.
For medically supported answers to all the questions you’ve ever had about cracking your knuckles, keep reading!
It’s a simple question, but one most of us have asked ourselves: What’s at work in the body when we hear that popping sound?
“Many believe that cracking knuckles is the bones realigning, which couldn’t be further from the truth,” says Weiss. Actually, the process has to do with your joints.
“Knuckling cracking is the audible sound that occurs when the joints of your fingers are stretched,” says Curda. “These joints are called synovial joints and are surrounded by fluid-filled capsule.” That fluid, called synovial fluid, is there for lubrication, and is made up of dissolved gases—mostly nitrogen, Curda says.
When you pull or bend your fingers (aka the two most common “cracking motions”), you stretch that fluid-filled capsule. This decreases pressure inside the gas-packed fluid, causing a small nitrogen bubble to form and then instantly pop. “The collapsing bubble is what causes the audible crack that we hear,” says Curda.
(Here’s a quick video of the whole process, if you want a helpful visual.)
As for why the sound is so dang loud, science still isn’t totally sure. However, they do know why you can’t crack the same joint over and over again.
“The gases take about 20 minutes to fully dissolve back into the fluid,” says Curda. That’s the refractory period—the amount of time that needs to pass until you can get cracking again.
“Aside from some degree of compulsion [aka decades of habit], cracking the knuckles actually releases several pounds of pressure from the joints,” Weiss explains.
As you use your hands throughout the day and the muscles tighten up, the joints end up feeling tight as well. “Cracking the knuckles gives your fingers and joints a stretch to relieve that pressure buildup,” says Curda. In other words, people crack their knuckles for the same reasons they might take a nice, big stretch in the middle of the day. It’s a feeling of ahhhhhhh.
So, what separates the normal people from us knuckle-popping junkies? “People that use their hands and fingers regularly during the day without otherwise stretching will feel the need more often,” says Curda. So, writers, coders, surgeons, those people who paint teeny-tiny messages on grains of rice.
But knuckle-cracking dependence goes further than that. Once you get into the habit of cracking, you become hooked on that feeling of relief—even the sound itself, says Weiss. “Cracking the knuckles is definitely addicting,” he affirms. It’s not something you can stop on a dime (no matter how much your family members and co-workers complain).
Ah, the million-dollar question. I always wrote off the warnings of arthritis the same way I ignored my grandmother when she told me if I crossed my eyes enough they’d get stuck that way.
Though the phenomenon is somewhat under-studied, science agrees: “There is no evidence that cracking your knuckles has any detrimental effect on your body,” says Curda. Intrinsically, there’s nothing about cracking your knuckles that leads to conditions like arthritis.
However, the worst of us knuckle crackers may not be totally off the hook. Bending the fingers to crack them can wear away the cartilage over time if you do it constantly, says Weiss. He recommends pulling the joint if you feel the need to crack, which is the “safest and most effective way to release the gas in your joints.”
That said, there is some disagreement on this topic, and more research needs to be done to evaluate the long-term effects of cracking. But at this point, the one outcome everyone can agree on is that cracking your knuckles will definitely annoy the people around you.
As far as I’m aware, there’s no formal support group for knuckle crackers. However, there are things you can do to lessen the urge.
“Hand, wrist, and forearm stretches performed regularly can help relieve the need to crack your knuckles as often,” says Curda. Every hour or two, try holding your hands in a prayer position in front of your face, then gently pull your hands downward toward your belly button until your elbows spread apart and you feel the stretch. Or, simply clench your hands into a light fist; then spread them wide apart, and repeat.
If you’re committed to leaving your knuckle-popping habit behind you, a certain level of willpower is also necessary, of course. But know that if you still crack a couple times a day, our docs say you’ll be just fine.
“Like all things in life, moderation is key,” says Weiss. So, feel free to take your knuckle cracks with your dessert.
Interested in more fascinating medical knowledge? Check out this story on how coffee affects your skin, according to science.