Artists, authors, philosophers, and scientists have long been fascinated with dreams. Greek philosopher Aristotle wrote an entire treatise on dreams, and William Shakespeare mused about dreaming in the tragedy “Hamlet.”
We still talk a lot about dreams today. We often muse about what they could mean. And we know that almost all people do dream, regardless of whether (or how well) they remember those dreams when they wake up.
But why do we dream? The short answer is scientists don’t really know for certain.
Regardless of why we dream, it’s interesting to take a closer look at dreams and how long they may last.
It’s hard to say how long an individual dream may last. But experts can provide estimates about how long you may spend dreaming.
According to the National Sleep Foundation, the average person dreams four to six times per night. You might spend as much as 2 hours in dreamland over the course of a night’s sleep, reports the National Institutes of Health.
Most of the dreaming seems to occur during rapid eye movement, or REM sleep. REM sleep is one of the two basic categories of sleep that your body experiences, with the other being non-rapid eye movement (NREM) sleep.
And while you can dream during NREM sleep, your dreams are more likely to be the most vivid during REM sleep.
REM sleep cycles tend to occur about every 1.5 to 2 hours. Your body will first enter REM sleep about 90 minutes after you fall asleep. But you might only remain in that first cycle of REM sleep for 5 minutes or so.
Later, when you cycle back through NREM sleep into REM sleep again, you may remain in REM sleep for a longer period of time.
You might spend a half-hour in a cycle of REM sleep as the night wears on. If you sleep for about 8 hours, you might spend approximately one-quarter of that time in REM sleep.
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
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.
It’s almost impossible to determine how many dreams you have in a typical night.
To complicate things, you may have dreams but wake up and have no memory of them.
Dreams seem to be irresistible to researchers, who continue to explore the science behind them. Here are some other interesting facts about dreams and dreaming:
- Kids dream in NREM sleep. Children under 10 years old dream much more often in the NREM stage of sleep than in the REM stage of sleep. In fact, the REM stage only accounts for about 20 percent of their dream time.
- Your body is basically paralyzed while you’re dreaming. During REM sleep, your eyes will flutter or move quickly, but your major muscle groups will become temporarily paralyzed. The cause of the paralysis has been intensely debated and investigated, but some research in rats suggests neurotransmitters inhibit certain motor neurons during REM sleep, causing the paralysis.
- Some people seem to act out dreams in their sleep. That’s because they experience REM sleep behavior disorder (RBD). It can cause you to act out your dreams while you’re sleeping.
- Your brain may choose what to forget while you dream. A
2019 studyexplained that neurons producing melanin-concentrating hormone (MCH) seemed to impair the memory-making function in a part of the brain called the hypothalamus during REM sleep.
- Medications can affect your dreams. For example, beta-blockers lower your blood pressure, but they might also amp up the intensity of your dreams.
- Some people dream in black and white. Age may be a factor. Older people who watched more black-and-white television seemed to dream more often in gray scale than younger people who grew up with full-color media, according to one 2008 study.
When it comes to dreams, everyone is different. Maybe you rarely, if ever, recall any of your dreams. Or maybe you may frequently wake up with a vivid recollection ringing in your head.
But regardless of whether you remember your dreams or not, you do dream at various points in the night, if you sleep long enough.
It’s just your brain at work in a nightly process with some still-to-be-determined goal.
If you start to experience nightmares on a recurring basis, though, contact your doctor. Your nightmares could be the result of an underlying medical condition that can be addressed.