Can you remember having a nightmare? The American Academy of Sleep Medicine estimates that somewhere between 50 and 85 percent of adults say they’ve had a nightmare.

There doesn’t seem to be a definitive answer about how long a typical nightmare lasts. But experts note that nightmares do tend to happen in later cycles of REM sleep, often in the last third of the night.

Women are more likely than men to report that they’ve had nightmares. There are numerous potential causes, including stress and anxiety or certain medications.

And while anyone can have an occasional heart-pounding nightmare, some people experience regular episodes of nightmare-filled sleep.

Some of these nightmares can be attributed to PTSD, while others may not seem to have a readily identifiable cause.

Nightmare disorders are relatively rare: According to the American Academy of Sleep Medicine, about 4 percent of adults have a nightmare disorder.

But research suggests as many as 71 percent of people who’ve experienced trauma have regular nightmares.

There are treatment options available to help people with nightmare disorder, including image rehearsal therapy and cognitive behavioral therapy.

So, if you think you may be affected, talk to your doctor.