Here what happens to your knuckles when you crack them.

If you pop or crack your joints, you probably
do.

What happens to our joints when we crack them?

And is it bad for you?

Synovial fluid is this lubricant-like substance
that's found in between your joints.

It kind of looks like an egg yolk.

So when you stretch out your joint, you are
releasing gas, and that gas forms a bubble

and it collapses and pops.

In order to crack the same knuckle again,
you have to wait about 20 minutes for the

gas to return back to that fluid.

So how is that different from a pop you hear
when you stand up quickly?

The sound you're probably hearing then is
the snapping sound tendons make when slide

between muscles or over bones.

When a joint moves, the tendon snaps quickly
over and it makes a popping sound.

So is the knuckle cracking habit safe?

Probably.

Donald Unger was sort of a self-described
researcher who chose to pop the joints in

one of his hands for 60 years, but not the
other one.

And he wanted to find out if popping your
knuckles would actually give you arthritis.

After 60 years of doing it, he found that
he didn't have any more arthritis in one hand

than in the other.

But there's still a chance it's not good for
you.

One 1990 did find that cracking your knuckles
over a long period of time led to hand swelling

and decreased scrip strength, but there hasn't
been any follow-up research on that.

So while cracking your knuckles might not
be bad for you, there's still no guarantee

that your popping habit won't annoy the people
around you.