how long do dreams last?
Gathering evidence from research studies, it can be assumed that an average dream last mins to 20-30 mins and does not go beyond 45 minutes.
Dreams are among the most fascinating and intriguing aspects of sleep. Sigmund Freud first laid out the Psychoanalytical theory in the late 19th century, which helped place emphasis on the significance of dreams. Although they have been the subject of much psychological and neuroscience research only in the last century, many cultures historically have speculated on the nature of dreams and the unconscious mind. Despite years of scientific research, there are many mysterious questions regarding dreams that lack conclusive answers. One of these is the actual length of an average dream.
It’s difficult to say how long an average dream lasts. Here’s what we do know though: The human body experiences two types of sleep, rapid eye movement (REM) and non-rapid eye movement (NREM) sleep. Dreams typically occur during the REM sleep cycle, which seems to happen 90 minutes after falling asleep. During REM sleep, brain activity is high, similar to being awake. Sometimes dreams may happen during the NREM cycle, but these dreams are much less vivid.
How long does REM sleep last?
The first REM stage lasts for about five minutes. REM sleep cycles usually occur every 1.5 to 2 hours, and each REM stage tends to last longer. The last stage before awakening can last for 45 minutes and up to an hour. According to the National Sleep Foundation, the REM cycle accounts for at least 20 percent of sleep, and the average person dreams four to six times per night, though most of these dreams are less likely to be memorable.
Even so, the length of dreams is still a subject of discourse. Experts believe since REM sleep can last about 45 minutes, dreams can be that long. But this remains inconclusive because there is no possible way to measure the time spent dreaming.
Correlation between REM time and dream time
There have been notable research carried out on the length of dreams. William C. Dement, a pioneer in sleep research, concluded that perceived dream time was similar to real-time after conducting two studies. Dement observed subjects while sleeping and recorded the time their rapid eye movement lasted. He then woke up the subjects and asked them to write down the contents of their dreams. He found that the number of words in the subject’s dream journals were consistent with REM time. This measure of using Total Word Count or Total Recall Count from sleep mentation reports to measure dream time is used to this day.
This method was further substantiated by observing subjects with REM behavior disorder, or RBD. RBD is a sleep disorder, or more specifically a parasomnia that features people acting out their dreams and sleep talking during REM sleep. Dement monitored and recorded the timings of sleeptalking and muscle movements. As a result, the timings in sleep mentation reports correlated strongly with the recorded timings.
Dream sequence vs. dream time
Arguably, REM time is no longer considered a reliable measure of dream length. This is because dreams may occur in other sleep stages. Dreams are difficult to record, and it is possible to have dozens of dreams in a single night. Moreover, studies suggest the dream sequences may be varied.
Matthew Wilson’s research on memory consolidation in dreams has shown that dream sequences, in many instances, are disjointed, on a quicker time-scale, and even in reverse order of the events represented in the dream. Think of it like fast-forwarding a film. The passage of time in the film is much more rapid, as opposed to real-time, but you are conscious of the actual passage of time. This is believed the be true while dreaming as well; dreams may occur at a faster speed, but dreamers are conscious of the passage of time in real life.
Do animals have dreams?
Although it is uncertain whether animals have dreams, recent research has concluded that “it seems very likely”. In fact, research from MIT has suggested that animals have complex dreams and can remember and recall long sequences of events in their sleep.
Wilson and colleagues trained rats to run along a circular track to be rewarded with food. The rats’ brain activity was monitored during the activity and when they had fallen asleep. During the task, the rats’ brain created a unique pattern of neurons firing in the hippocampus, a part of the brain associated with memory.
Much like humans, rats also drift through multiple cycles of sleep, from slow-wave to REM sleep. After examining more than 40 REM cycles recorded while the rats slept, it was discovered that almost half repeated the same distinctive signature of hippocampal activity from when the rats were traversing the track. The researchers found that the animals dreamed, they could replicate exactly the rat would be in the maze if it was awake.
The dream imagery in the rats represented the critical points of the maze, like obstacles and intersections, over less stimulating parts of the maze such as long hallways. It’s quite simple, really: like a tourist taking photos. There would be fewer images of boring parts like the hotel room, and more photos of monuments and beaches. Conversely, dreams do not necessarily occur at a consistent speed, they may change to be faster and slower according to the events of the dream.
With that being said, it still remains uncertain whether the phenomenon that was observed in Wilson’s rats translates to human dream. The point remains that there is a difference between being conscious of the actual passage of time and the length of scenarios reflected in that time.
How long do nightmares last?
Nightmares can be defined as dreams that feature frightening or anxiety-inducing events, which may result in awakening from sleep. According to the American Academy of Sleep Medicine, up to 85 percent of adults say they have experienced nightmares.
Nightmares can result in other sleep-related health issues, such as insomnia, daytime fatigue, stress, and anxiety.
There seems to be a lack of a definitive answer about how long a nightmare lasts. Despite this, experts believe that nightmares typically occur in the later stages of REM sleep.
Although nightmares are a common occurrence, they may become concerning if one experiences frequent episodes of nightmares in their sleep. Some of these nightmares can be due to PTSD, while others may be due to stress, emotional upheaval, substance abuse, illness, or side effects of medication.
Nightmare disorders are quite rare, around 4 percent of people experience a nightmare disorder. But research suggests that as many as 71 percent of people with past trauma experience regular nightmares.
Treatment options for people afflicted with nightmare disorder include image rehearsal therapy and cognitive behavioral therapy
How long do lucid dreams last?
Daniel Erlacher at the University of Bern carried out an experiment to examine brain activity during lucid dreaming. Lucid dreams are mainly considered to be experienced during REM sleep cycles. Lucid dreamers can consciously influence events in the dream, and thus, they are able to execute predetermined tasks while in lucid sleep. Lucid dreams are especially helpful for studies regarding the passage of time in the dream state.
The subjects of this study were asked to complete a task in lucid sleep and real life. The activity took almost 50 percent longer to perform while in lucid sleep than in actuality. This could also offer an explanation as to why many people have dreams of running in slow motion.
Why do we dream?
There still exists discourse among sleep researchers as to why we dream. There are numerous theories on why dreams occur.
As discussed before, dreams play an important role in consolidating memories. This indicates that dreaming may be critical in the cognitive function of retention of memory and recall. Dreams can help us understand and process emotions, especially complex ones. This can also be viewed as a survival tactic and can help process past experiences of trauma and abuse. Periods of dreaming can also allow for the brain to remove unnecessary and partially encoded information. Dream imagery may allow counterfactual memories and events to be reviewed and examined by the brain. This is consistent with Wilson’s maze study. It is also believed that dreaming serves no real purpose and holds no meaning, many researchers view it as a by-product of sleep.
Other interesting dream facts
Dreams are a subject of much psychological research. Dreams are mysterious and interesting occurrences, the science behind them even more so.
Interestingly, children under the age of 10 frequently dream in the NREM cycle of sleep, unlike adults who typically dream in the REM stage of sleep. Since REM sleep only accounts for one-third of a night, it is assumed children have more dreams.
During REM sleep, while the brain activity is high and eye movements are rapid, we experience temporary muscle paralysis. The cause of this phenomenon is unknown but heavily debated. Some research in rats indicates the presence of certain neurotransmitters that inhibit specific motor neurons.
According to a study conducted in 2019, neurons responsible for producing melanin-concentrating hormone (MCH) resulted in impaired memory functioning in the hypothalamus. This suggests that the brain may choose to forget information while dreaming.
Some people experience monochromatic dreams. This is more common in older people who were more exposed to black-and-white cinema, and less likely to occur in younger people who had exposure to full-color television. Colorblindness may also result in seeing dreams in grayscale.
Medications can alter dreams, for instance, beta-blockers for high blood pressure may increase the intensity of dreams. Anti-depressants, drugs, and alcohol can also affect your dreams.
Although researchers continue to study sleep phenomena like dreams and parasomnia, it may be impossible to prove any theory definitively, at least with current technology. As for now, there is no short answer regarding the length of dreams. It can be estimated and examined, but there are currently no methods to conclusively record the length of a dream. Moreover, individual dreams are subjective experiences, some may have up to seven dreams in a night, while others may only have three. Subjective experiences such as dreaming often do not hold an objective, definitive solution. In the meantime, gathering evidence from research studies, it can be assumed that an average dream does not go beyond 45 minutes.