Why do we dream? The purpose and impact of dreams on sleep
Clinically reviewed by Dr. Chris Mosunic, PhD, RD, CDCES, MBA
It's something we all do, but why do we dream? Learn how dreams work, the science behind the purpose of dreams, and how dreams impact the quality of our sleep.
Even though dreams are a universal human experience, scientists are still trying to fully understand what happens when we close our eyes at night. While theories offer some insights, the mystery of why we dream keeps experts (and the rest of us) endlessly fascinated.
Why do we dream? The purpose of dreams
Humans spend about two hours a night dreaming, yet we often don’t remember most of our dreams. When we remember them, dreams can be fun and exciting, but they can also be puzzling, unsettling, and even scary. It’s thought that dreams could play a crucial role in our emotional and cognitive wellbeing by helping with many parts of our emotional life.
Dreams help us process our emotions
Dreams may be your brain's way of helping you process the emotions you experience during the day. After a particularly tough day, your brain sifts through the jumble of emotions, deciding what to hold onto and what to let go. Dreams can help you process your feelings, making problems less daunting after a good night’s sleep. A good idea might even pop up in your sleep from your time spent dreaming.
Dreaming can also serve as an emotional release, allowing you to confront feelings you might have suppressed. That dream where you're floating, or flying might be your subconscious encouraging you to let go of a worry weighing you down. Or maybe you have unfulfilled ambitions of being a pilot. Unfortunately, we don’t know the specific meanings behind dreams yet, but it’s interesting to ponder them.
Dreams support memory consolidation
Your brain sorts, prioritizes, and declutters memories while you sleep. The theory is that dreams help organize information acquired during the day as your brain decides whether each experience is a memory to keep or let fade away.
Dreams have evolutionary benefits
Our early human ancestors faced daily threats to their survival. It's possible dreams were a way to practice real-life scenarios, like escaping a wild beast or finding shelter in a storm. These dreams could have prepared our ancestors to deal with real-world situations without any actual risk.
Dreams remain an area of active research. So, while we may have some answers, scientific understanding is still developing.
How long does it take to start dreaming?
Many of us wonder what our minds do each night while we’re asleep. And while we know that sleep occurs in cycles, and that dreaming is a part of those cycles, how dreams affect each stage of sleep is fascinating.
Understanding the sleep cycle
A series of cycles: Throughout the night, your brain cycles through various stages of sleep, each lasting around 90 minutes. It starts with lighter sleep, plunges into the deeper stage, then becomes lighter again.
When dreams come alive — the REM stage: During the rapid eye movement (REM sleep) stage, the brain is nearly as active as when it's awake, meaning that dreams are most vivid and story-like. REM typically starts about 70 to 90 minutes after you first fall asleep.
Non-REM vs. REM: While the REM stage brings the most intense dreaming, you can also dream during the non-REM phases of sleep. Dreams in these stages are often less cinematic and more thought-like.
What happens when you dream?
Dreaming often feels like stepping into a world filled with unexpected encounters, strange plot twists, and even invaluable insights. When we dream, we enter a complex neurological and psychological state characterized by vivid mental imagery, emotional shifts, and varying levels of awareness.
Neurotransmitters like serotonin and hormones like melatonin and cortisol play a role in shaping our dreams. While dreams are primarily visual, they can also involve all other senses.
💙 If you’re curious to try and remember your dreams, a dream journal can help you remember them. This can promote mindfulness and self-reflection. Try Calm’s Dream Journal to capture dream memories and discover patterns—or just enjoy the amazing tales your mind creates for you at night.
How do dreams impact sleep quality?
Contrary to popular belief, dreaming doesn’t disrupt your sleep. In fact, it's a natural part of your sleep cycle. However, there’s an exception to this and that’s nightmares. These dark or disturbing dreams can jolt you awake, interrupting your sleep and creating micro-moments of distress that can be hard to forget when it’s time to return to your pillow.
Why do we have nightmares?
Nightmares can have a huge impact on your sleep and can sometimes leave you jolting upright in bed with a racing heart or a sweaty forehead. Nightmares might be completely nonsensical or they might mirror a real-life fear or trauma. These bad dreams are often associated with childhood, but adults can experience them too. They typically reflect stress, fears, or underlying psychological concerns.
Nightmare triggers
Daytime stress: One of the most common culprits behind nightmares is the stress you experience during waking hours. This could be because of work pressures, relationship issues, or global events. Processing these stresses can lead to intense dreams.
Past traumas: Events from the past can resurface in your dreams. These dreams can sometimes recur until you find a way to process the trauma.
5 ways to keep nightmares at bay
While it isn’t likely that scientists will ever find a total ‘cure’ for nightmares, there are strategies that can help manage and even help prevent nightmares. Even though nightmares can be distressing, they serve a purpose. They’re a testament to your brain’s incredible capacity to process, heal and grow.
1. Try relaxation techniques before bed
Bring relaxation techniques into your bedtime routine, for example, deep breathing exercises or progressive muscle relaxation. These methods help calm the mind, making it less likely to produce distressing dreams.
💙 Relaxing with some gentle stretching and movement can get you relaxed and ready for a peaceful night’s sleep. Explore Evening Wind Down from the Daily Move.
2. Establish a sleep routine
Going to bed and waking at the same time, even at weekends, can help regulate your sleep schedule and reduce the likelihood of nightmares. The key to establishing a sleep routine is making it something that you look forward to each night. Maybe you have a cup of herbal tea, take a relaxing shower, or dive into your favorite book.
💙 You can also press play on one of our Sleep Stories like, Dream With Me read by Harry Styles.
3. Limit your exposure to stressful content
Setting yourself up for a peaceful night’s sleep starts by monitoring what you put into your mind before you lay down for the night. Try to avoid news, movies, or books that might be distressing right before bedtime, as these can influence your dreams.
💙 Try reading a book you love while listening to a peaceful soundscape like Jasper Lake or City Rain.
4. Talk about your nightmares
Sometimes, discussing a recurring nightmare can help reduce its power. If you’ve got one that’s plaguing you make a plan to talk about it. Share it with a trusted friend, family member, or therapist. You can also journal about it to get it out of your mind and on paper.
5. Tune into guided sleep practices
Sometimes the best way to wind down for bed is to have some gentle guidance from a meditation teacher. Engaging in guided sleep meditations can help shift the mind's focus from daily stresses into a peaceful night’s rest.
💙 Unwind into Sleep with Chibs Okereke will help you settle in using relaxing body awareness and soothing breath work.
Why do we dream? FAQs
Why do dreams feel so real?
Dreams often feel incredibly real because they involve the same regions of the brain that are active when we’re awake. When dreaming, especially during the REM (Rapid Eye Movement) phase, our brain processes emotions, sensory experiences, and memories, much like it does during our waking hours. So even though you're safely tucked up in bed, your dreams can feel like a genuine experience.
Why do we forget dreams?
One popular belief is that we're designed to forget non-essential information. Since most dreams don't directly affect our survival or daily life, they're discarded. Another idea suggests that the neurotransmitters responsible for memory aren’t as active during sleep. So, while we may remember snippets right after waking up, those dream memories fade as the day progresses.
Can you feel pain in dreams?
Interestingly, it's rare to experience physical pain in dreams. However, people sometimes feel emotions related to the experience. For instance, you might dream of being afraid of getting hurt rather than the actual pain. The brain's pain receptors aren't active while you sleep, so feeling physical pain is uncommon.
Are there people who don't dream?
Everyone dreams, but only some remember their dreams. Some people might recall their dreams frequently, while others might only remember them occasionally—or believe they don't dream at all. Several factors, including sleep quality, stress, and even genetics, can influence dream recall.
How long do dreams last?
Dreams can vary in length, from a few seconds to about 20-30 minutes. Typically, dream duration increases with each REM cycle, with the longest and most vivid dreams occurring towards the morning.
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