Many people feel stiff when they wake up, but for some people the prolonged aching could mean the beginning of rheumatoid arthritis.

It isn’t uncommon for people to be stiff and achy when they awaken after a good night’s sleep. But in some cases, morning stiffness for a prolonged period of time could be an early indicator of rheumatoid arthritis.

According to the Arthritis Foundation, if morning stiffness lasts for more than one hour, it could mean the beginning of rheumatoid arthritis (RA), the autoimmune form of arthritis.

Researchers reached the same conclusion in a study that was published earlier this morning.

Joint stiffness can occur in one or multiple joints. It can be mild, moderate, or severe in its intensity.

The intensity doesn’t necessarily indicate whether it’s osteoarthritis, aging, or RA, but the duration of the stiffness could.

If morning stiffness exists for a prolonged period of time — in this case one to two hours — for an extended duration, people should call their primary care doctor or rheumatoid arthritis specialist to rule out RA.

Medical professionals can perform a battery of tests that may include bloodwork, X-rays, bone scans, physical exam, and other imaging.

You can use a diary to keep track of symptoms like morning stiffness, said Tina Burke, a health coach in Pennsylvania.

“Jotting down symptoms in a journal, like stiffness, soreness, and fatigue, and also tracking how many days and for how long symptoms exist could be helpful to show a doctor,” Burke told Healthline. “I also like the idea of food journaling to see if food exacerbates symptoms.”

Some say that morning stiffness was their first indicator of a problem.

“I had pain and stiffness every time I woke up. It was ridiculous. I told my doctor and at first they were not concerned, but eventually tested me for RA, and I had it,” Stacey Hoover of Pennsylvania told Healthline.

Any body part can be affected by morning stiffness, but many patients experience it in their hands and knees.

While RA has no cure, early diagnosis and early treatment can help improve outcomes.

The Arthritis Foundation recommends seeing a rheumatologist if morning stiffness persists.

If morning stiffness lasts for under a half an hour, it may be osteoarthritis.

But if it’s closer to an hour or two, the culprit is likely RA.