New research shows that dreaming actually serves a number of important functions, especially for learning and memory.

By Frank Lipman, MD, and Neil Parikh

Even though we think of sleep as “powering down,” our brains are doing anything but that when we get shut-eye. Without any incoming stimulation or thoughts, the brain uses this valuable free time to perform maintenance and admin—cleansing, consolidating memories, and imprinting new information. And we now know that dreaming is an important part of these nocturnal activities.

Scientists used to think that dreams were just a byproduct of the brain’s nighttime regimen. However, new research has shown us that dreaming actually serves a number of important functions, especially for our learning and memory. But if you’re not sleeping well (not reaching deep sleep or waking up multiple times a night), then you’re missing out on one more essential tool that your brain needs in order to keep you healthy and sharp.

Even though you may not know whether you’re dreaming on a regular basis (we dream at all stages of sleep, not just REM, and don’t necessarily remember all the content), it’s safe to say that if you’re consistently cycling through all four stages of sleep without regular interference (meaning you’re getting a full, restful night’s sleep), then you’re going to reap the benefits of dreams. The advantages of nighttime dreaming are numerous.

Dreams help us store memories and the things we’ve learned.

The brain reactivates and consolidates newly received memories and information tidbits while we sleep, and researchers have seen that this process is directly reflected in the content of our dreams. But some experts believe that dreams aren’t just reflecting what we need to know and remember, they’re actively cataloging it. Their findings suggest that our dreams are a sort of virtual reality experience as we witness this memory processing. Experiments in both animals and humans support the theory that our dreams are like a “rehearsal” of that new information, allowing our brain to put it into practice and actively organize and consolidate the material.

Dreams help process our emotions.

Recent research suggests that we’re more likely to dream about emotionally intense experiences, and the theta brain waves during REM sleep are one way in which the brain consolidates those memories. This has led some researchers to examine how REM sleep plays a role in trauma recovery and mood regulation, owing to its hand in processing difficult experiences.

Even nightmares have benefits.

Nightmares occur most frequently in REM sleep, but unlike lucid dreams, these intense, often unwelcome imaginings happen with decreased prefrontal cortex activity, meaning there’s less emotional control and a more overwhelming sense of arousal. Researchers now believe that these experiences are the brain’s way of preparing us for when bad things happen, like an emotional “dress rehearsal.” It’s almost as though the mind is anticipating bad things happening, and then trying out solutions. Some experts believe that this is a defense mechanism rooted in our earliest days—if something bad happened once, there was a chance it could happen again. So having a recurring nightmare of that event could keep you on guard.

At the very least, dreams offer another way of looking at things.

Dreams don’t just simply replay what we’ve experienced or learned, they also create brand-new mashups and free associations between what we’ve seen and what we know. As a result, our dreams offer a portal into our deepest, most unfettered creativity, as well as to new approaches to problem-solving. This is most evident in the testimonies of famous artists and thinkers who credit their dreams with inspiring some of their greatest creations, like Paul McCartney and the melody for “Yesterday” or Dmitri Mendeleev and the structure for the periodic table of elements.

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What Your Dreams Say About Your Sleep

The nature of your dreams can lend insight into what cycle of sleep you’re dreaming in:

Stage 1: During this fuzzy, foggy time just before you drift off or wake up, dreams are usually short but feel vivid and visceral, like having the sensation of “falling” to sleep. Because you’re still in a semi-awake state, these dreams often incorporate real- world content like noises you’re actually hearing (your alarm, a siren outside).

Stage 2: In this lighter stage of sleep, dreams usually include pieces of real-life events from the day. They’re often described as being “thought-like,” as though you’re merely processing different ideas while you sleep. As you revisit stage 2 sleep throughout the night, your dreams will gradually get longer and more vivid.

Stage 3: Even though your brain is still active during deep sleep, your dreams are typically the least vivid during this stage as your brain tends to memory processing and cognition renovation.

REM: This is the stage of sleep that’s most frequently associated with dreams. Dreams that occur during these more “active” peaks in your sleep cycle are the ones you usually remember most: they’re typically the longest, most vivid, and most bizarre. (We also get a lot of REM sleep in the morning, so the timing is more conducive to remembering these dreams.) Also, this is the stage of sleep when the emotional parts of the brain are most active, which is what experts suspect makes our REM dreams feel more poignant and affecting.

Bestselling author Frank Lipman, MD, who focuses on functional medicine, and Neil Parikh, co-founder of Casper, are the authors of Better Sleep, Better You (Little, Brown and Company, 2021).

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