Our dreams can be exhilarating or frightening, but why do we dream, and what do vivid dreams really mean?

A tiger with wings soars through your window. You’re back in fifth grade, but your teacher is a giant swamp monster. You walk up to a buffet table full of immaculate desserts, but suddenly the floor is made of clouds. You slip through and find yourself falling . . . seemingly to your doom!

You awaken with a start. It was all a dream.

As you begin your morning routine, you might feel like you just lived through a busy day while you were sleeping. Why does it seem like when your body is completely at rest, your brain is working overtime?

Dreams are where we go to stir up our thoughts, fears, wishes, secrets, and memories into a whirlwind of the odd or absolutely absurd. This wild world takes on many forms. Dreams can resemble real-life scenarios, vivid memories, or completely invented situations—in which we may or may not be directly involved. Sometimes we seem to just watch the action before us as if playing a movie in our heads.
And while some are fascinated by dreams, others think they have a secret significance. Some cultures have associated dreams with a connection to other worlds or segments of time. However, many scientists have labeled dreams as an important feature of our physical and mental health.

The science of sleep

Sleep isn’t just an enjoyable activity (especially on those rare weekend mornings when you can sleep in). Sleep is also an essential process for human function, a period in which the heart, lungs, and other organs that must work continuously can slow down to a more relaxed pace. Meanwhile, many systems of the body take some much-needed time off. In these seven to nine hours of vital rest, the body can regenerate, the immune system can cleanse the body of illnesses, and the brain is free to get silly.

As our brain cycles through different phases of sleep, we eventually descend into the rapid eye movement, or REM, stage. The deepest and most important phase, REM sleep is when most dreams occur—and when the brain enters a powerful state with proven benefits for our health.

The creative, familiar, and just plain weird

Dreams help us to rebuild and expand neural pathways, the information networks that the brain uses to learn, remember, and grow. As Erik Hoel, research assistant professor at Tufts University, states, dreams assist in “breaking the cycle of repetitive daily tasks—filling out spreadsheets, delivering mail, tightening pipe fittings—with an infusion of discord, keeping our brains fit.” This means that the bizarre, scary, or even romantic scenarios we invent during sleep introduce our brains to more information.

What if you’re in a car accident tomorrow? If you’ve ever dreamed of such a scenario, Hoel suggests that this was your brain’s way of preparing you to handle such a stressful event in the real world. In a sense, dreams can keep the mind flexible, prepared, and adaptable to various unpredictable situations.

What about nightmares?

Your twilight adventures in the world of dreams may often take the form of nightmares, stressful or even terrifying dreams that feel all too real. Maybe you enter your home to find it’s been flooded and destroyed; maybe you forget a major work deadline, and your boss is after your head. Some of the most unwelcome dreams are those that tie into our instinctual fear of shame. These dreams may involve being inappropriately dressed in public or having to give a performance for which we’re deeply unprepared.

Despite how they may feel, nightmares can be surprisingly healthy, reinforcing what our brains consider vital information. Have you ever dreamed about a swarm of spiders or falling into ice-cold water? These dreams underline the importance of fear for self-preservation. We should avoid interacting with snakes, for example, because our dreams show us the consequences these threats have for us, such as painful bites and venom.

While occasional nightmares are completely normal, if you have nightmares often you may be suffering from parasomnia. According to Verywell Mind, “Nightmare disorder is considered a parasomnia, a type of sleep disorder that interferes with a person’s sleep by creating abnormal or undesirable experiences.” Some people even experience what are known as night terrors, periods of intense fear in which they shake, yell, or exhibit other signs of distress in their sleep. They may or may not wake up during these frightening episodes.

Nightmare disorder and night terrors are often associated with anxiety, depression, and other mental health conditions. However, having the occasional nightmare isn’t necessarily a sign of a mental health concern.

Recurring dreams may also be obnoxious or even disturbing. Many experts suggest that this is your mind’s way of highlighting a certain emotion or fear. However, these dreams can be debilitating if you frequently remember them. Those who have recurring dreams about a traumatic event should consider reaching out to a mental health expert for treatment. As with nightmare disorder and night terrors, talking to a therapist about difficult recurring dreams can help you find relief.

To dream or not to dream

On the opposite end of the spectrum, did you know that some people don’t dream at all? Thanks to a rare and little-known condition called aphantasia, such people cannot conjure mental imagery in their heads. Aphantasia makes certain mental tasks, like picturing the face of a loved one, nearly impossible. For many of these individuals, scary nightmares may not be a concern, but they also may never experience the thrilling and fantastical dreams that have fascinated the rest of us since the dawn of humankind.

Remembering your dreams

Many people feel that dreams have a more spiritual significance, like connecting them with those who have passed or even predicting the future. The power of dreams, ultimately, is up to your perspective—and your spiritual beliefs—to determine. If you feel that dreams are important to you, try keeping a dream journal next to your bed. Be sure to write about your dreams in detail as soon as you wake up, before you forget the vivid experiences and return to life in the real world.

For more info, visit sleepfoundation.org/dreams