A favorite party trick of mine is to crack my hips dramatically. No, not crack, pop. I have really obnoxiously loud hips, probably because I had displaced hips as a baby or maybe because of the years I spent as a ballet dancer. Still, whenever I crack my hips on demand, it gets a reaction, because the sound grosses people out.
But it's extremely normal for people's joints to crack, and the reason why it makes a sound isn't that freaky at all. "Our joints contain the gases oxygen, nitrogen, and carbon dioxide, which make up something called synovial fluid," says Armin Tehrany, MD, board-certified orthopedic doctor and surgeon at Manhattan Orthopedic Care. The role of synovial fluid is to lubricate your joints, according to MedlinePlus. "When our joints are overextended, the synovial fluid will create gas bubbles that ultimately produce the pop or crack sound you hear," Dr. Tehrany says. While it might sound loud depending on the person, cracking is totally fine.
Maybe you're not like me, and you find that your joints only crack during a workout. That's also normal, because that's often when your body is moving the most during your day. Occasionally though, you might be hearing a different kind of cracking during a workout, Dr. Tehrany says. "Sometimes when a joint moves, the tendon that surrounds it may move out of place," he says. When that tendon shifts back into its place, then you might hear a snapping or cracking sound, he says. Although that might seem a little scary or intense, it's not really something to worry about. Changing the type of movement that causes a crack or stretching is usually enough to make it go away.
Contrary to popular belief, cracking your joints is not necessarily a bad thing. But sometimes cracking joints can be a sign of arthritis or early degeneration of the joint surface, which is known as crepitus, Dr. Tehrany says. Young people can experience crepitus, although it's more common in older individuals. Often people experience this in their knees, but it's also common in hips, shoulders, and the spine. "Look out for signs of pain, swelling, limited mobility or warmth near your joints and the area that is cracking or popping," he says. Those can be signs of a bigger issue that would require a doctor's attention.
So, whether you're someone who gets freaked out by the sound of popping joints, or you're worried about how much you crack, it's still a good idea to stay active. Moving throughout the day can keep your joints lubricated, and prevent the noise, according to the Cleveland Clinic.