Why Do We Dream? Here Are 3 Possible Reasons

How often do you remember your dreams after waking up? Sometimes, a dream can rattle you to your core, causing you to get out of bed feeling distressed. Other times, you may feel excited. But, most mornings, you likely don’t have any recollection of the two hours your brain spent dreaming.

So why is it that we dream? Below, two sleep specialists explain the importance of dreaming and some possible reasons why we do it. But first, it’s helpful to understand how your brain enters a dreamy state. 

What happens in the brain during a dream? 

Collectively referred to as sleep architecture, there are different stages of sleep that we cycle through in the night:

• Stage 1: moving from a state of being awake to falling asleep

• Stage 2: non-REM (rapid eye movement) sleep that involves entering a light sleep

• Stage 3: non-REM sleep that is deep and restorative

• Stage 4: REM sleep, which is the deep sleep when most dreaming occurs and when sleep paralysis (a sleep disorder that prevents you from moving or speaking)can occur

“In stages 1 and 2, we have lighter non-REM sleep, but in [later] stages we have our deepest, most physically restorative sleep,” Shelby Harris, PhD, a clinical psychologist specializing in behavioral sleep medicine and the director of sleep health at Sleepopolis, told GoodRx Health.

“After about 90 minutes of falling asleep, we go into REM sleep. This is when our brains are the most active and when we have the majority of our dreams. But you can dream at any stage,” she continued. 

Harris added that the brain processes emotions, memories, and thoughts during REM. “And then we cycle back through the lighter stages of sleep,” she said, noting that we go through each stage of sleep four to six times each cycle. 

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Why do we dream? 

There is still so much we don’t know about dreaming, according to Christopher Winter, MD, a neurologist, sleep specialist, and host of the “Sleep Unplugged” podcast. However, there are a few working theories on why the brain drifts off into dreaming. Below, we look into three of them.

1. Dreaming to process an event

“Many think that dreaming allows us to have a mental ‘sandbox’ for rehearsing an event or analyzing a trauma in a safe space,” Winter told GoodRx Health. 

This may explain why certain snapshots or moments from your life are often incorporated into dreams, even if they appear in strange ways. 

Think about it: Have you ever revisited a difficult conversation you had with a loved one or colleague in a dream? This is your brain’s way of processing that emotion-driven event. The same goes for joyful events; you may relive a fun day with friends or getting a promotion in your dreams. 

2. Dreaming to solidify memories

Another theory in the “why we dream” debate, Harris explained, is that dreaming is the brain’s way of consolidating information or memories from the day. 

“Dreams allow your brain to figure out what information is useful to remember, and what information you don’t need and can forget about,” Harris said.

3. Dreaming to clear your mind

A third theory suggests that dreaming is the way the brain rids itself of useless thoughts — almost like clearing away the clutter. 

To illustrate this theory, Harris equated dreaming to the brain’s personal filing cabinet. “It’s going through your experiences from the day and sorting through what it needs to keep and what it can throw away,” she said.

Do dreams mean good sleep?

On its own, remembering dreams isn’t a strong sign of quality sleep, Harris explained. Most people don’t rememberwhat they dreamed about upon waking up.  

“Everyone dreams, but not everyone will be able to recall their dream the next morning. So, if you aren’t able to remember your dream, it doesn’t necessarily mean you didn’t get a restful night’s sleep,” Harris said.

In fact, she added, having vivid or recurrent, disturbing dreams could be a sign of a bigger issue, including sleeping too much. 

When dreaming may signal an underlying health condition

“Strangely enough, many people who have very healthy sleep do not report dreaming. Excessive dreaming often indicates sleep is being fragmented,” Winter said, adding that dreaming too much can be a sign of sleep apnea. 

If someone has obstructive sleep apnea (OSA), it means the person’s upper airway collapses and blocks the back of the throat while they are sleeping. 

“Because dreaming is associated with paralysis, apnea happens more during dreaming,” Winter said. She added that some people only experience sleep apnea during REM. Sleep apnea can collapse the airway and cause the person to wake up and remember their dreams.

New research suggests that upsetting dreams might be linked to a higher risk of Parkinson’s disease. In this study, scientists noticed that participants who had more than one bad dream per week were three times more likely to be diagnosed with Parkinson’s disease within the next 5 years. 

But it’s important to point out that this was an incidental finding. That means scientists weren’t looking for or studying this association — they found it by chance. So it’s unclear how  distressing dreams and Parkinson’s disease are related. 

Since the study was originally done to investigate bone fractures in older men, scientists don’t know how dreaming and Parkinson’s are connected in other groups or younger people. 

Indicators of good sleep

So, if remembering your dreams isn’t necessarily linked to healthy sleep, what is? Winter described healthy sleep as striking a balance between length and quality. When you wake up, you should feel recovered and rested, she said. 

And, according to the CDC, adults 18 to 60 need at least 7 hours of sleep every night to maintain good health.

Is it possible to sleep without dreaming?

Yes, it’s very possible to sleep without dreaming. However, there is a difference between not being able to recall your dreams and not dreaming, Harris emphasized again.

“Sleep disorders, such as insomnia and sleep apnea, can prevent the brain from reaching REM sleep, which is where we have the majority of our dreams,” Harris said. “But the vast majority of us actually dream; [it’s just that] not everyone remembers them.”

Aside from sleep conditions, Winter added, certain medications and substances can negatively affect sleep quality by diminishing REM sleep and, in turn, dreaming. She pointed to how alcohol, specifically, can negatively impact sleep quality, despite it having sedative effects. That’s because it interrupts both the deeper and lighter stages of sleep, which is the reason why you may wake up several times after a night of drinking.

And research has indicated that some antidepressants — including benzodiazepines and a range of selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) — can impair sleep, especially in the short term. 

Why do I forget my dreams so quickly? 

Remember, you can think of dreaming as your brain’s way of doing daily housekeeping. “People forget their dreams, most likely, because the process is in some way related to culling or pruning memories that are deemed not worth keeping,” Winter said. 

Harris added that dreams are often stored in our short-term, as opposed to long-term, memory. This could be another explanation for why people are often quick to forget them.

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Written by:

Cheyenne Buckingham, BS

Cheyenne Buckingham is a journalist and editor who specializes in nutrition, women's health, fitness, food injustice, and the relationship between chronic disease and diet. She has 6 years of experience covering food, health, wellness, and fitness.

Edited by:

Samvida Patel, MNSP, INHC

Samvida Patel, MNSP, INHC, is a health editor at GoodRx. She is a nutritionist and integrative nutrition health coach with over 8 years of experience in health communications.

Reviewed by:

Sanjai Sinha, MD

Sanjai Sinha, MD, is a board-certified physician with over 20 years of experience. He specializes in internal medicine.

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