You swing your legs over the side of the bed, stand up, and your knees sound like a bowl of Rice Krispies. Your ankles join in. Maybe your neck, too. Sound familiar?
Here is the reassuring part: that crackling and popping is extremely common, and it even has a name. It is called crepitus. And most of the time, it is nothing to worry about.
Pamela Mehta, MD, a board-certified orthopedic surgeon and sports medicine physician who runs Resilience Orthopedics in San Jose, California, told Reader’s Digest the real reason behind it.
Why It Happens in the Morning
Crepitus can show up in virtually any joint in the body, but it is most common in the knees, shoulders, neck, ankles and knuckles, according to Dr. Mehta.
Morning is prime time for it. “You’ll hear it more in the first few movements you make because your joints feel stiffer after a night of not moving,” she says. “Once you’re warmed up, this usually quiets down.”
Knee crepitus affects about 41 percent of the general population. It becomes more noticeable as we get older because cartilage (the cushioning between your bones) thins over time. “Your joints are stiffer and less elastic, so there is more for the joint to catch on,” Dr. Mehta explains.
What Is Actually Causing That Sound?
There is more than one explanation for joint noise, and Dr. Mehta walked us through the most common ones.
Tiny gas bubbles. The fluid inside your joints (called synovial fluid) contains small gas bubbles. When you move first thing in the morning, those bubbles can release. “You can hear it, and you can sometimes feel it if you place your hand over the joint,” Dr. Mehta says. This is the same basic thing that happens when you crack your knuckles.
Extra-flexible joints. Some people are simply born with a wider range of motion and may notice more crepitus as a result. Muscle weakness or imbalances can also play a role. Dr. Mehta says many people find the noise decreases as they build stronger, more balanced muscles around the joint.
Tendons catching on bone. A duller click or snap that happens at the same point during a specific movement is often a tendon flicking over a bony edge. Dr. Mehta says this is especially common on the outside of the hip when you swing a leg out or get up from a chair. It is usually harmless.
Osteoarthritis. People with osteoarthritis are more likely to experience crepitus, including 81 percent of people with knee arthritis. But Dr. Mehta is clear on something important: popping or grinding joints do not mean you have arthritis or that you will develop it. “A grinding or gravelly feeling, especially behind the kneecap, can be linked to changes in the cartilage,” she says. “But it doesn’t always mean something is damaged.”
A previous injury. If you have ever injured a joint, like a meniscus tear in the knee or a dislocated shoulder, you are more likely to notice crepitus in that spot later on.
When Should You Actually See a Doctor?
The noise itself is not the problem. How the joint feels is what matters.
“If it doesn’t hurt, it’s usually nothing to worry about,” Dr. Mehta says. “But if you feel pain, swelling or stiffness (especially if it’s getting worse over time ) see an orthopedic doctor. I’d also want to see you if the joint locks, catches or gives way, or if this is a new thing that came on suddenly or after an injury.”
One situation that needs prompt attention: a joint that becomes very swollen and you cannot put weight on it after an injury. And Dr. Mehta says a hot, swollen joint combined with a fever needs urgent care.
Can You Do Anything About It?
You may not be able to make crepitus disappear completely, but you can often reduce it. The key is building strength around the joint.
“Patients who build up their thigh and hip strength often find their knees feel better, even if the noise doesn’t fully go away,” Dr. Mehta says. “Strong muscles take pressure off the joint.”
Options include physical therapy, strength training, or bodyweight exercises like squats and lunges combined with moderate cardio. Maintaining a healthy weight also takes load off the knees and hips.
So the next time your knees announce your arrival at breakfast, take it as your cue to get moving. A little warm-up, some steady strengthening, and chances are things will quiet down before your first cup of coffee is done.
