Dreams: Why We Dream & How They Affect Sleep | Sleep Foundation

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• What Are Dreams?
• Why Do We Dream?
• When Do We Dream?
• Do Dreams Have Meaning?
• What Are Types of Dreams?
• What Are Nightmares?
• How Can You Remember Dreams?

Key Takeaways

• Dreams are mental, emotional, or sensory experiences that take place during sleep.
• Dreams are the most common and intense during REM sleep when brain activity increases, but no one knows for sure why we dream.
• Dreaming is normal and healthy, but frequent nightmares can interfere with sleep.
• Waking up gradually and journaling your dreams may help you remember them better.

Dreams are one of the most fascinating and mystifying aspects of sleep. Since Sigmund Freud helped draw attention to the potential importance of dreams in the late 19th century, considerable research has worked to unravel both the neuroscience and psychology of dreams.

Despite this advancing scientific knowledge, there is much that remains unknown about both sleep and dreams. Even the most fundamental question — why do we dream at all? — is still subject to significant debate.

While everyone dreams, the content of those dreams and their effect on sleep can vary dramatically from person to person. Even though there’s no simple explanation for the meaning and purpose of dreams, it’s helpful to understand the basics of dreams, the potential impact of nightmares, and steps that you can take to sleep better with sweet dreams.

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What Are Dreams?

Dreams are images, thoughts, or feelings that occur during sleep. Visual imagery is the most common Trusted Source National Library of Medicine, Biotech InformationThe National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information.View Source, but dreams can involve all of the senses. Some people dream in color while others dream in black and white, and people who are blind tend to have more dream components related to sound, taste, and smell Trusted Source National Library of Medicine, Biotech InformationThe National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information.View Source.

Studies have revealed diverse types of dream content, but some typical characteristics of dreaming include:

• It has a first-person perspective.
• It is involuntary.
• The content may be illogical or even incoherent.
• The content includes other people who interact with the dreamer and one another.
• It provokes strong emotions.
• Elements of waking life are incorporated into content.

Although these features are not universal, they are found at least to some extent in most normal dreams.

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Why Do We Dream?

Debate continues among sleep experts Trusted Source National Library of Medicine, Biotech InformationThe National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information.View Source about why we dream. Different theories Trusted Source Division of Sleep Medicine at Harvard Medical SchoolA production of WGBH Educational Foundation and the Harvard Medical School Division of Sleep Medicine.View Source about the purpose of dreaming Trusted Source National Center for Biotechnology InformationThe National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information.View Source include:

• Building memory: Dreaming has been associated with consolidation of memory, which suggests that dreaming may serve an important cognitive function of strengthening memory and informational recall.
• Processing emotion: The ability to engage with and rehearse feelings in different imagined contexts may be part of the brain’s method for managing emotions.
• Mental housekeeping: Periods of dreaming could be the brain’s way of “straightening up,” clearing away partial, erroneous, or unnecessary information.
• Instant replay: Dream content may be a form of distorted instant replay in which recent events are reviewed and analyzed.
• Incidental brain activity: This view holds that dreaming is just a by-product of sleep that has no essential purpose or meaning.

Experts in the fields of neuroscience and psychology continue to conduct experiments to discover what is happening in the brain during sleep, but even with ongoing research, it may be impossible to conclusively prove any theory for why we dream.

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  Do Dreams Impact Sleep Quality?

When Do We Dream?

On average, most people dream for around two hours per night. Dreaming can happen Trusted Source National Library of Medicine, Biotech InformationThe National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information.View Source during any stage of sleep, but dreams are the most prolific and intense during the rapid eye movement (REM) stage.

During the REM sleep stage, brain activity ramps up considerably compared to the non-REM stages, which helps explain the distinct types of dreaming Trusted Source National Library of Medicine, Biotech InformationThe National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information.View Source during these stages. Dreams during REM sleep are typically more vivid, fantastical, and/or bizarre even though they may involve elements of waking life. By contrast, non-REM dreams tend to involve more coherent content that involves thoughts or memories grounded to a specific time and place.

REM sleep is not distributed evenly through the night. The majority of REM sleep happens during the second half of a normal sleep period, which means that dreaming tends to be concentrated in the hours before waking up.

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  How Long Do Dreams Last?

Do Dreams Have Meaning?

How to interpret dreams, and whether they have meaning at all, are matters of considerable controversy. While some psychologists have argued that dreams provide insight into a person’s psyche or everyday life, others find their content to be too inconsistent or bewildering to reliably deliver meaning.

Virtually all experts acknowledge that dreams can involve content that ties back to waking experiences although the content may be changed or misrepresented. For example, in describing dreams, people often reference people who they recognize clearly even if their appearance is distorted in the dream Trusted Source National Library of Medicine, Biotech InformationThe National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information.View Source.

Dream Interpretation

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What Are the Types of Dreams?

Dreams can take on many different forms. Lucid dreamsoccur when a person is in a dream while being actively aware that they are dreaming. Vivid dreams involve especially realistic or clear dream content. Bad dreams are composed of bothersome or distressing content. Recurring dreams involve the same imagery repeating in multiple dreams over time.

How to Lucid Dream

Is Lucid Dreaming Dangerous?

Vivid Dreams, Explained

What Are Precognitive (Premonition) Dreams?

What Is a Fever Dream?

Nightmares vs. Dreams

In sleep medicine, a nightmare is a bad dream that causes a person to wake up from sleep Trusted Source National Library of Medicine, Biotech InformationThe National Center for Biotechnology Information advances science and health by providing access to biomedical and genomic information.View Source. This definition is distinct from common usage that may refer to any threatening, scary, or bothersome dream as a nightmare. While bad dreams are normal and usually benign, frequent nightmares may interfere with a person’s sleep and cause impaired thinking and mood Trusted Source American Academy of Sleep Medicine (AASM)|National Library of Medicine, Biotech InformationView Source during the daytime.

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  Why We Have Nightmares

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  How to Stop Having Nightmares

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  Nightmares in Children

How Can You Remember Dreams?

For people who want to document or interpret dreams, remembering them is a key first step. The ability to recall dreams can be different for every person and may vary based on age Trusted Source Nature and Science of SleepView Source. While there’s no guaranteed way to improve dream recall, experts recommend certain tips Trusted Source American Psychological Association (APA)APA is the leading scientific and professional organization representing psychology in the United States, with more than 121,000 researchers, educators, clinicians, consultants and students as its members.View Source:

• Think about your dreams as soon as you wake up. Dreams can be forgotten in the blink of an eye, so you want to make remembering them the first thing you do when you wake up. Before sitting up or even saying good morning to your bed partner, close your eyes and try to replay your dreams in your mind.
• Have a journal or app on-hand to keep track of your dream content. It’s important to have a method to quickly record dream details before you can forget them, including if you wake up from a dream in the night. For most people, a pen and paper on their nightstand works well, but there are also smartphone apps that help you create an organized and searchable dream journal.
• Try to wake up peacefully in the morning. An abrupt awakening, such as from an alarm clock, may cause you to quickly snap awake and out of a dream, making it harder to remember the dream’s details.
• Remind yourself that dream recall is a priority. In the lead-up to bedtime, tell yourself that you will remember your dreams, and repeat this mantra before going to sleep. While this alone can’t ensure that you will recall your dreams, it can encourage you to remember to take the time to reflect on dreams before starting your day.

Dream FAQs

Do Blind People Dream?

What Is a Dream Journal Used For?

What is a False Awakening?

Can Trauma Affect Dreams?

Do Lucid Dream Masks Work?

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