The conditions of the brain during sleep do not allow the dream to be transferred to long-term memory upon awakening.
In addition, a lack of the hormone noradrenaline, which is responsible for long-term memory, also plays a role.
Another reason could be that neurons from the hippocampus do not work properly during the REM sleep phase, which prevents them from transferring information to other neurons, delivering sleep never stored in memory.
Why we dream
Let’s start with why and when dreaming occurs. Dreaming tends to take place during REM sleep, which can occur multiple times a night. This sleep stage is characterized by rapid eye movement (what REM stands for), increased bodily movement, and faster breathing.
Mike Kisch, co-founder and CEO of Beddr, a sleep tech start-up, tells Healthline that dreaming tends to occur during this time because our brain wave activity becomes more akin to that of when we’re awake. This stage usually begins about 90 minutes after you fall asleep, and can last for up to an hour toward the end of sleep.
“Whether they remember or not, all people do dream in their sleep. It is an essential function for the human brain, and also present in most species,” Dr. Alex Dimitriu, double board-certified in psychiatry and sleep medicine and founder of Menlo Park Psychiatry & Sleep Medicine, tells Healthline. So if everyone dreams, why don’t we all remember them?
That answer can vary depending on which theory of why humans dream you decide to follow, because there’s quite a few. Dream research is a wide and complex field, and dreaming can be hard to study in a laboratory. This is partly because the brain activity can’t tell us about the content of dreams, and you have to rely on subjective accounts from people.
Why some people remember and others forget
Lambert tells Healthline that if someone consistently doesn’t get enough sleep, the amount of REM sleep they experience will drop, making it harder for them to remember their dreams the following day.
Even personality traits can be an indicator of whether someone will be able to remember their dreams.
Lambert continues: “Researchers also looked at the most common personality traits that are presented in people who can recall their dreams. Overall, such people are prone to daydreaming, creative thinking, and introspection. At the same time, those who are more practical and focused on what is outside themselves tend to have difficulty remembering their dreams.”
This may mean that some people are naturally more likely to recall their dreams than others, despite their quality of sleep.
Other factors, like stress or experiencing a trauma, can also cause people to have vivid dreams or nightmares that they’re more likely to recall the next day. For example, a person who’s coping with grief after losing a loved one may dream about the death in elaborate detail. Remembering the dream the next day may affect mood and cause even more stress or anxiety.
As a writer who’s constantly daydreaming and focused on introspection, this doesn’t surprise me. In fact, as I’ve grown, the way I view my dreams, itself, has evolved. For most of my childhood, I would watch myself in third person, almost like a movie. Then, one day, I started experiencing the dreams through my own eyes, and it never reverted.
Sometimes my dreams will build on each other, even expanding on a previous event’s dream in a current one. This could be a sign of my brain continuing its storytelling in my sleep.
Does dreaming affect sleep quality?
While I was worried about my dreaming being a sign that I’m not sleeping well, it turns out dreaming itself doesn’t affect sleep quality. Though being able to remember dreams can sometimes be a sign of something else, such as a health condition or medication.
“While there may be some biological differences that result in some remembering dreams more than others, there are also some medical causes that should be considered. Alarm clocks, and irregular sleep schedules can result in abrupt waking during dream or REM sleep, and thus result in recall of dreams. Sleep apnea, alcohol, or anything that disturbs sleep can also cause dream recall,” Dimitriu says.
So the more you’re waking up throughout the night, the easier it may be to remember your dreams, at least in the short term. “In most cases, this happens because there’s something alerting that nudges us awake during dreaming, and in turn the dream content is recalled,” Dimitriu says.
What about those dreams that are so intense or disturbing that they literally wake you out of your sleep? You may find yourself in a sweaty panic, your heart racing, and sitting up in bed totally confused about what just happened. Dimitriu explains that having dreams or nightmares that regularly wake you up isn’t always normal and may be a sign that you need to speak to a doctor.
People who have post-traumatic stress syndrome (PTSD) may have vivid nightmaresTrusted Source that involve flashbacks or replays of the trauma, either directly or symbolically. These can affect sleep quality and mood the next day.
Also, excessive fatigue during the daytime may be a sign of sleep issues that require a person to seek help. If at any point your dreams, or remembering your dreams, is causing you stress or anxiety, you should consider speaking with a doctor.
While researchers still aren’t sure what exactly causes dreaming, it’s a relief to know that remembering your dreams is a common, healthy thing. It doesn’t mean you aren’t sleeping well, and it definitely doesn’t mean you’re crazy or “not normal.”
Though I do feel more tired at times when waking up from a detailed dream, remembering them keeps things interesting — not to mention, it gives me some great story ideas. Aside from the time I dreamed about snakes for an entire week. That’s a tradeoff I’ll take.
How to Better Remember Dreams
If you are interested in improving your dream recall, consider a simple change: keep a dream journal. By keeping a pen and a notebook on the nightstand next to the bed, it becomes easy to quickly record dreams immediately upon awakening, before they have had a chance to fade.
Writing down your dream may encourage improvements in dream recall. If the scribbled notes can be interpreted later in the morning, it may be possible to reflect on the meaning of your dreams.
How Long Do Dreams Last?
REM sleep lasts only a few minutes early in the night but gets longer as we sleep. Later in the night, it might last more than 30 minutes. So you might spend half an hour in a single dream.
Tips for Dream Recall
If you’re a sound sleeper and don't wake up until the morning, you’re less likely to remember your dreams, compared with people who wake up several times in the night. Some tips may help you remember your dreams:
Wake up without an alarm. You’re more likely to remember your dreams if you wake up naturally than with an alarm. Once the alarm goes off, your brain focuses on turning off the annoying sound, not on your dream.
Remind yourself to remember. If you make a decision to remember your dreams, you’re more likely to remember them in the morning. Before you go to sleep, remind yourself that you want to remember your dream.
Dream playback. If you think about the dream right after waking, it may be easier to remember it later.