My name is Shep, and I live in Nashville, Tennessee, and you're listening to Sleep Tight Science.
Did you know that kids dream more than adults?
Because their brains are learning so many new things every day.
What?
No wonder it's a dream party in your head.
Hello friends and welcome back to Sleep Tight Science a bedtime show that answers your questions about science.
Everyone dreams.
Everyone has had a dream that felt a little strange or exciting or even frightening.
You might have woken up with your heart beating fast, looking around your room and felt relieved that it wasn't real.
This kind of experience is common and normal.
And tonight, we're going to talk about why it happens.
Did you know that right now, while you're awake and listening, your brain is quietly getting ready for tonight's sleep?
And tonight, while you're sleeping, your brain will be busier than you might think?
In this episode, we are going to try and answer the following questions.
Why do we have nightmares? and what's happening in our brain while we sleep.
We'll start with what sleep cycles are and the different stages your brain moves through each night.
Then we'll explore what dreams and nightmares or bad dreams are and why bad dreams happen.
Finally, we'll talk about what you can do when bad dreams visit and why they're actually a normal part of how your brain learns and processes the world.
You don't have to remember every word or everything we talk about all at once.
You can try to remember this.
Sleep isn't one flat thing.
It's a journey through different stages, and dreams, including scary ones, are your brain's way of sorting, practicing and making sense of the day.
Before we continue, here are some words to listen for.
Sleep cycle.
A pattern of stages your brain moves through during the night, repeating every 90 minutes or so.
REM sleep.
Rapid eye movement sleep, the stage where most vivid dreams happen.
Deep sleep, the stage where your body does repair work and your brain rests most deeply.
Dream brain activity during sleep that creates images, feelings and stories.
Nightmare or bad dream.
A dream that causes fear or distress, usually during REM sleep.
A quiet thank you to Shep, seven years old from Nashville, for introducing our show.
And to all our curious friends who send in questions.
You help us learn together.
Take a few deep belly breaths.
As you do, think about what you might dream tonight.
Will you fly high up in the sky, flying to your favorite treat shop?
Or will you dream about being warm and cozy in your bed, surrounded by all the things you love?
One last belly breath.
Good.
If you are ready, let's start learning about your brain's nighttime journey.
When you fall asleep, your brain doesn't just shut down like a computer powering off.
It begins a journey. moving through different stages, each with its own job to do.
Scientists call this pattern a sleep cycle, and each cycle lasts about 90 minutes.
During a full night's sleep, you move through four, five or even six complete cycles.
Your brain moves through these stages in a specific order and each stage has a purpose.
Let's follow the path.
Light sleep is where the journey begins.
This is the drifting off stage where you're not quite awake and not quite asleep.
Your muscles start to relax.
Your heart rate slows.
Your breathing becomes steadier.
It's easy to wake someone from light sleep.
A small sound or a gentle touch might bring them right back.
Scientists can measure what's happening in your brain using sensors that detect brain waves.
Tiny electrical patterns that show how active your brain is.
During light sleep, those waves start to slow down like ripples on a pond, calming after someone stops splashing.
After light sleep comes deep sleep, and this is the stage where your body gets to work.
Deep sleep is the hardest stage to wake from.
If someone calls your name, you might not even hear it.
Your brain waves slow way down, long rolling waves instead of quick ripples.
During deep sleep your body is busy growing, healing cuts and bruises, strengthening your immune system so you can fight off germs, and even clearing away the buildup That happens when your brain works hard all day, like wiping down a whiteboard so it's fresh and ready for tomorrow.
You don't usually dream much during deep sleep, or if you do, the dreams are fuzzy and forgettable.
Deep sleep is about repair, not stories. something interesting happens.
After deep sleep, your brain doesn't stay in that slow, quiet place.
It starts to become active again, but you don't wake up.
Instead, you enter a stage called REM sleep, which stands for rapid eye movement.
The name comes from what your eyes do.
Even though your eyelids are closed, your eyes move quickly back and forth underneath, as if you're watching something.
And in a way, you are.
You're watching a dream.
During REM sleep, your brain becomes almost as active as it is when you're awake.
It's busy sorting through memories, deciding what to keep and what to let go.
It's practicing skills you learned during the day.
It's processing emotions, happiness, worry, excitement, fear, and trying to make sense of them.
And while all this is happening, your body is mostly paralyzed.
Your muscles relax so completely that you can't move much, except for your eyes and your breathing.
Scientists think this paralysis is your body's way of keeping you safe, so you don't act out your dreams and accidentally hurt yourself.
This is the stage where most vivid dreams happen.
The ones you remember.
The ones that feel real.
After REM sleep, the cycle starts again.
Back to light sleep. down into deep sleep, back up to REM.
Over and over, all night long.
But here's something important.
The cycles aren't exactly the same each time.
Early in the night, you spend more time in deep sleep.
Your body prioritizes repair first.
Later in the night, and especially in the early morning hours, you spend more time in REM sleep.
Your brain prioritizes sorting and dreaming.
That's why you often remember dreams from just before you wake up.
You've been spending more time in that active dreaming stage.
Babies spend almost half of their sleep time in REM.
Their brains are building and learning so much that they need extra sorting time.
Adults spend about 20 to 25% of their sleep in REM.
Kids and teens are somewhere in between, because your brain is still growing, still learning, still making sense of a big, busy world.
So sleep isn't one thing.
It's a journey with stages, each one doing important work.
Your body repairs itself during deep sleep.
Your brain sorts, practices, and processes during REM.
And all of it happens in cycles, rolling gently through the night while you rest.
In the next part we'll look closer at dreams themselves, why they feel so strange, why some turn into bad dreams, and what your brain is actually trying to do when it creates them.
Let's start with the definition of a dream.
Dreams are brain activity during sleep, especially during REM sleep, that creates images feelings, sounds and stories.
Your brain is mixing together memories from the day, emotions you felt, things you learned, worries you had, and sometimes completely random bits, all stirred together into something that feels real while it's happening.
Dreams can be wonderful flying over your neighborhood, talking to your favorite book character, climbing a mountain of ice cream, discovering a secret door in your house.
They can be silly, showing up to school in your pajamas, your dog suddenly speaking French.
They can be confusing, jumping from one scene to another with no connection.
And sometimes they can be spooky.
Scientists think dreams help your brain with several important jobs.
Memory consolidation means your brain is deciding what to keep and what to let go, like sorting through papers and deciding which ones to file and which ones to recycle.
Emotional processing means working through feelings from the day, especially the big ones that didn't get fully sorted while you were awake.
Problem solving happens too.
Your brain keeps working on puzzles even while you sleep, which is why sometimes you wake up with an answer you couldn't find the day before.
And practice and rehearsal.
Your brain simulates situations to help prepare you for things that might happen.
Dreams feel strange because the logical planning part of your brain, the part that helps you think step by step during the day, is much less active during REM sleep.
Meanwhile the emotional and memory parts are very active, so dreams feel intense and real, but the storylines can be weird and jumpy.
You might be at school, then suddenly at the beach, then back home, and your dreaming brain doesn't question it.
Bad dreams are dreams that cause fear, anxiety, or distress.
They usually happen during REM sleep, which means they often come later in the night or early in the morning when you're spending more time in that stage.
Everyone has them.
They're completely normal.
In fact, they're more common in kids than in adults.
And scientists think that's because your brain is processing so many new experiences, new places, new people, new feelings.
And sometimes that processing includes things that feel spooky or uncertain.
So why do bad dreams happen?
Sometimes it's because of stress or worry.
Your brain is trying to work through something that felt confusing or frightening during the day.
Sometimes it's because of big changes like moving, starting a new school, or family shifts.
Your brain is sorting through uncertainty.
Overactive imagination can play a role too.
Creative kids often have more vivid dreams, including bad dreams.
Being overtired can make bad dreams more likely, because when you're exhausted, your brain has trouble regulating emotions during sleep.
And sometimes a bad dream is your brain's way of processing something you saw or heard a scary story, a movie or even news, trying to make sense of it.
Here's what bad dreams are not.
They're not predictions of the future.
They're not signs that something is wrong with you.
They're not punishments.
And even though people sometimes say, it's just in your head, that phrase misses the point.
Bad dreams feel real because your emotional brain is very active during REM sleep.
The fear is real, even if the story isn't.
Some scientists think bad dreams might actually be useful.
They might be your brain's way of practicing how to deal with fear in a safe space.
Your brain rehearses what to do if something scary happens, so you're more prepared if you ever face something difficult in real life.
Processing emotions during sleep, even scary ones, helps your brain learn and grow stronger.
Close your eyes for just a moment and imagine.
Your brain at night, sorting through a big pile of the day's moments.
Some happy, some confusing, some a little strange.
It holds each one up to the light, decides what it means, then files it away or lets it drift off like smoke.
Some moments need more sorting than others.
That's okay.
Your brain is working.
We'll talk about what helps your brain settle before sleep and what you can do if a bad dream visits next.
Here are some things you can try.
When you wake up from a dream, try to notice how you feel.
Your heart might be beating fast.
You might feel relieved it wasn't real.
That's your body shifting from the dream state back to being awake.
Notice, too, how dreams fade quickly once you're up.
That's normal.
Your brain isn't great at moving dream memories into long-term storage, so they slip away like mist.
Pay attention to whether you remember dreams more in the morning.
That's because you're spending more time in REM sleep closer to wake-up time.
If you have a bad dream, here are a few things that help.
A calm bedtime routine makes a difference.
By listening to our show, you are already making an effort.
You might try Sleep Tight Relax too, where we help with teaching various relaxation techniques and tell a story.
Your brain takes the day's mood into sleep with it.
Gentle activities before bed reading, listening to our podcasts, soft music, slow breathing help your brain settle.
Avoiding intense content close to bedtime gives your brain less to sort through.
Talking about worries during the day helps too.
If something is bothering you, Talking about it while you're awake gives your brain less work to do at night.
Your awake brain is much better at problem solving than your dreaming brain.
When you wake from a bad dream, look around the room.
Notice you're safe.
Some kids find it helpful to change the ending of a bad dream while they're awake, drawing a new version or telling the story differently.
It reminds your brain that you have control.
After a bad dream, it's okay to get up, get a drink of water, talk to a grown-up, then go back to sleep.
Your brain will move into a different sleep stage and the bad dream usually won't come back that night.
If bad dreams happen very often and make you afraid to go to sleep, or if they're about something that actually happened and feel stuck in your mind.
Talk to a grown-up.
There are ways to work through persistent bad dreams And talking helps.
Tomorrow at breakfast you might talk about whether you usually remember your dreams or what the strangest dream you can remember was.
So back to our question.
We have bad dreams because our brain is actively processing emotions and experiences during REM sleep.
And sometimes that includes fears or worries.
Sleep cycles move us through different stages.
Deep sleep for body repair, REM sleep for brain sorting.
And dreams, including bad dreams, are a normal part of how our brain learns and makes sense of the world.
Here's a wave to some of our question askers.
Max Hansen, age 9, Crown Point, Indiana.
Albert, 5 years old, from Maine.
Josephine S., from Huntersville, North Carolina.
Mira, age 6, from Custer, South Dakota.
Joseph, age 7, and Freddie, age 5, from New Jersey.
Lulu, age 6, from the Philippines.
Autumn, 8 years old, from Canada.
Nora Pang, 6 years old, from Hangzhou, China.
Remi, age 5, in Suquamish, Washington.
Akif, 10 years old, from Toronto.
Jack H, 8 years old, from Louisiana.
Madeline from Colorado Springs, Colorado.
Dia Malikarjuna, age 7, from Muscon, Oman.
Felix Digweed in the UK.
And Leo, age 5, in New Mexico.
Thank you for asking questions that spark our curiosity and keep us learning.
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Ask your parents to help you.
Write us a note to the email address in our episode notes.
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It helps other people find our show.
Did you know that your brain goes on a journey every single night while you sleep?
Tonight, you might dream about some of the things we talked about.
Moving through different sleep stages, sorting memories like papers on a desk, or even watching your brain clean away the day's clutter like cleaning up after a big project.
Maybe you'll dream about something wonderful.
Flying over your neighborhood, discovering a secret room, talking to your favorite character from a book.
Maybe you'll dream about something puzzling showing up somewhere in your pajamas, or your pet suddenly speaking.
And if a dream feels a little scary, that's just your brain practicing, sorting through a worry, working something out in its own strange way.
Your brain knows how to do this work.
It's been doing it every night of your life.
Some dreams are bright and golden.
Some are gray and stormy.
All of them are your brain learning, growing, and making sense of the world.
So rest easy tonight.
Your brain is on duty, moving through its quiet rooms, doing its important work.
And when morning comes, you'll wake up and whatever you dreamed will have done its job and drifted away.
From Cheryl and Clark, good night, sleep tight.
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