Why do we dream? Experts share the 4 most important roles dreams play in our sleep

For most of us, dreaming can feel, well, quite dreamy. From acting out our wild fantasies to living our ideal lives, dreams are our brain's way of sorting through emotions and real-life scenarios.

But, how do dreams work? Most dreaming occurs during REM (rapid eye movement) sleep, a stage of the sleep cycle where brain activity increases, the body becomes temporarily paralyzed, and vivid dreams take shape.

Dreams are thought to play an important role in our sleep and health. But what really goes on in the brain while we sleep? We talk to the experts and explore the science behind what your sleeping mind is trying to tell you.

What is dreaming?

Around 80 per cent of us remember our dreams if we're woken during REM sleep, according to research. Many of us will have been able to recall a weird or frightening dream when we wake up, but what is dreaming?

“Dreaming is a mental and neurological experience that typically occurs during REM sleep (rapid eye movement) when the brain becomes highly active, but the body remains in a semi-paralysed state (so we don't act out our dreams in a dangerous way),” explains sleep expert Dr. Leah Kaylor.

She adds that dreams can often involve “vivid imagery, emotional intensity, and a story-like structures.”

How do dreams work?

We may look peaceful as we sleep, but as we run through different stages of sleep, a lot is going on in the brain. A sleep cycle consists of four stages, three NREM (non-REM) sleep stages, including deep (or slow-wave) sleep, and REM sleep.

Sleep medicine physician Dr. Emma Lin explains that some areas of your brain become active during REM sleep.

“This includes the limbic system, responsible for managing emotions, the hippocampus, which processes memory and the amygdala, which is responsible for fear and stress,” she says.

At the same time, the prefrontal cortex becomes less active. “This is the reason dreams become strange or erratic, but that is also the reason they assist your brain in awesome methods,” says Dr. Lin.

One study on dreams showed that 65% of the participants' dreams reflected elements of real-life experience, but they may not be completely similar.

Dr. Kaylor explains that the brain pulls from past experiences, emotions and even random thoughts to create dream ‘scenes’.

“The emotional and memory centres of your brain are in high gear, while the part responsible for logic is mostly offline," she explains.

"So you might find yourself flying, talking to someone who passed away, or solving problems in ways that don’t make sense in real life.”

What role do dreams play?

Some researchers believe that dreaming plays an important role on our physical and mental health, by helping us to consolidate memories or process tough situations.

However, other researchers believe they may be random — and have no correlation to our waking lives. Here are some of the ways studies show the role they could play.

1. Consolidate memories

Studies have shown that REM sleep plays a role in memory consolidation (which is the process by which short-term memories are converted into long-term memories).

According to Harvard Health, REM sleep is important as it is when you "process and consolidate new information you've learned."

Nurse Practitioner Shebna Osanmoh explains how dreams may be involved in memory consolidation.

“As you cycle through different sleep stages, the hippocampus tags recent experiences and helps transfer them to long-term storage in the cortex," he explains.

"Dreams often blend fragments of new and old memories and weave them into narratives that reinforce learning."

“For example, students studying for an exam frequently report dreaming about the material. This mental replay correlates with better recall the next day," Osanmoh adds.

Indeed, according to research, "learning-related dreaming predicts subsequent memory performance. In this sense, dreaming may be considered a reflection of the consolidation process."

Additionally, research has also proven that REM sleep is involved in the consolidation of emotional memories.

2. Process emotions

REM sleep is like a spring clean for your brain, with dreaming helping us to process strong emotions.

“Dreaming gives your brain a safe space to deal with tough emotions, like stress, anger, or fear without the pressure of being awake. It's kind of like an emotional detox,” says Dr. Kaylor.

“After a good night's sleep, things that felt overwhelming the day before often feel more manageable.”

While Dr. Sanam Hafeez, a neuropsychologist and director of Comprehend the Mind, explains that the “logical part of the brain is less active, which is why dreams often don’t make sense."

"Even though it feels like a lot is happening, dreaming is the brain’s way of processing and healing,” she says.

3. Practise our fight-or-flight response

Dreams can also be a practice run for dangerous situations, no matter how big or small, explains Osonmoh.

“By mentally practicing responses to potential dangers, being chased, arriving late, missing an appointment; the brain fine-tunes neural circuits for real-world coping," he says.

"Even benign daily tasks like giving a speech or navigating a new city may replay in dreams in simplified form," the nurse practitioner tells us.

“This anticipatory rehearsal helps sharpen both emotional and cognitive responses. So you’ll be more resilient and adaptable when similar situations arise while you are awake," he adds.

4. Help us problem solve

Ever woken up to the solution to a problem, which, the day before seemed unsolvable?

This is because “the brain can connect ideas in new ways while dreaming, since it’s not limited by logic," explains Dr. Hafeez.

"Sometimes, people wake up with answers to problems or creative ideas,” she adds.

What influences our dreams?

Outside influences can creep into our dreams, including factors such as stress and trauma, with Dr. Hafeez explaining that “stress often leads to intense or anxious dreams because the brain is trying to deal with strong emotions."

"Trauma can cause nightmares as the mind replays upsetting events to try and process them,” the doctor says.

While alcohol and drugs disrupt your sleep architecture, “They suppress REM early on," which can cause "rebound periods of intense REM later which often yield vivid, fragmented or disturbing dreams,” says Osanmoh.

“Anything that alters your neurochemistry or sleep structure, from caffeine intake to major life events can leave its imprint on your nightly mental theater," he adds.