Chapter 1: How Sleep Works

Chapter Introduction

Hi. I am the Cat.

We have met before.

If you read my G3 chapter — Your Sleep and You — you already know that sleep is not "off." You already know that while you sleep, your brain stays busy with different work. You already know that sleep helps your body grow and your brain save what you learned. You already know that all kids have hard sleep sometimes, and that when sleep stays hard, you tell a trusted grown-up.

Welcome back. The Cat is glad to see you again.

You are nine or ten years old now. You are bigger than you were at G3. You have slept many more nights since we last talked. Your body has grown a little. Your brain has saved many more memories. You can read longer chapters. You can hold more questions in your head at once. You are ready for the next step.

This chapter has three big ideas, and each one is one step beyond what we talked about at G3.

The first big idea is how sleep actually works. At G3 I told you sleep happens in cycles and your brain is busy in different ways. This time I will tell you more about those different ways. Sleep has parts — deep sleep and dream sleep — and each part does a different job. The parts come around again and again through the night.

The second big idea is how sleep helps you. The Turtle just wrote a chapter about how your brain learns (How Your Brain Works). The Turtle and I work very closely on this. The Turtle teaches that the brain learns through paying attention and practicing. The Cat teaches what happens at night — sleep is when your brain saves what was learned. Practice plus sleep equals learning that sticks.

The third big idea is the most important one, like at G3. Sometimes sleep gets hard, and when sleep stays hard for a while, that is something to tell a trusted grown-up about. The Cat has more to say at G4 about this than at G3, because you are older and ready for a slightly fuller picture.

Are you ready? Take a slow breath. Begin. Quietly.

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Lesson 1.1: How Sleep Actually Works

Learning Objectives

By the end of this lesson, you will be able to:

• Tell that sleep has different parts, not just one
• Describe what deep sleep and dream sleep are at a simple level
• Explain what a sleep cycle is and how cycles repeat through the night
• Notice that you can sometimes feel which part of sleep you woke up from
• Understand that different people at different ages need different amounts of sleep

Key Terms

The Cat Watches Again

The Cat has been watching humans sleep for a long, long time. At G3, I told you that sleep is not "off." Sleep is the brain doing different kinds of work than during the day. That is still true at G4.

What I did not tell you at G3, because you were a little younger, is that sleep has different PARTS. Different sections. Different stages — though I will just call them parts at G4, because the official names wait for when you are 11 or 12.

The Cat is going to tell you about two big parts now: deep sleep and dream sleep.

Deep Sleep — The Body Worker

The first part the Cat wants you to know about is deep sleep.

Deep sleep is the part of the night when your body does its strongest work. Quiet. Still. Almost like your body has gone underwater, where the surface noise cannot reach you. If someone tried to wake you up during deep sleep, it would feel really hard. You might feel groggy and confused if they did — that grogginess means they pulled you out of deep sleep [1].

During deep sleep, your body is busy doing things you cannot do while you are awake:

• Growing. Your body releases special chemicals called growth hormones — most of them come out during deep sleep. The Bear told you in Food and Your Body and How Food Becomes You that protein helps your body grow. The Cat adds: deep sleep is when most of that growing happens. Food + sleep = body building [2, 3].
• Repairing. All those little scrapes, bruises, sore muscles, scratched-up cells — your body works on fixing all of them during deep sleep.
• Fighting germs. Your body has a tiny army called the immune system that fights germs. The army does some of its best work during deep sleep. Kids who do not get enough sleep can get sick more often, partly because their immune system did not get to do its job [4].

Deep sleep happens MORE in the first part of the night. So the hours right after you fall asleep — the first three or four hours — usually have the most deep sleep. This is why bedtime matters. The earlier you fall asleep, the more deep sleep your body gets.

Dream Sleep — The Brain Worker

The second part the Cat wants you to know about is dream sleep.

Dream sleep is the part of the night when your brain is busiest. In dream sleep, your brain looks almost like it does when you are awake — fast, busy, full of activity [5]. Your eyes even move a little, side to side, behind your closed eyelids. (Scientists named this part of sleep using words about that eye movement. You will learn the official name in G6. For now, the Cat calls it dream sleep.)

This is when most of your dreams happen.

During dream sleep, your brain is doing the work the Turtle told you about in How Your Brain Works:

• Sorting what happened today. Your brain takes the day's events, conversations, and lessons, and decides what is important enough to keep.
• Saving what you learned. Remember when the Turtle said sleep is when your brain saves what you learned? This is when. Memory consolidation — saving memories — happens mostly during sleep, including dream sleep [6].
• Settling feelings. Big feelings from the day get worked through. Worries get a little smaller. Confusing things get sorted out. This is one of the reasons a hard day often feels a bit lighter in the morning.
• Making creative connections. Your brain links ideas in new ways during dream sleep. Some of the best ideas humans have ever had came right after sleep [7].

Dream sleep happens MORE in the second part of the night, especially the hours closest to morning. So when you wake up, you are often coming out of dream sleep — which is why some kids remember dreams right when they wake up but forget them as the day goes on.

Cycles — The Parts Come Around Again

Here is the part the Cat thinks is the most interesting.

Your sleep is not one big chunk of one thing. Through the night, you go through several cycles. Each cycle has some deep sleep, some lighter sleep, and some dream sleep. Then the cycle starts again. And again. And again.

One cycle takes about 90 minutes — about an hour and a half [1, 8]. So if you sleep for 9 hours, your body goes through about six cycles. If you sleep for 7.5 hours, about five cycles. If you sleep for 6 hours, about four.

The Cat is not going to make you do the math at G4. (You will do that math in G6.) The Cat just wants you to know: sleep is a series of loops, not one long stretch.

The cycles are not all the same. Early in the night, there is more deep sleep. Later in the night (toward morning), there is more dream sleep. This is one of the reasons why if you wake up early — say, before your alarm — you sometimes feel like you were just dreaming. You probably were.

It is also one of the reasons why getting enough sleep matters. A short night cuts off the last cycles — which means it cuts off the most dream sleep. Your body still got most of its deep sleep, but your brain missed some of its sorting and saving work.

Sleep Across Life

The Cat wants you to know one more thing in this lesson.

Different ages need different amounts of sleep. This is biology, not personality. Bodies and brains change as we grow.

• Newborn babies sleep about 14 to 17 hours a day, in many short pieces. (Their brains and bodies are growing so fast that they need a lot of repair time.) [9]
• Toddlers (1-2 years old) sleep about 11 to 14 hours.
• Young kids (3-5 years old) sleep about 10 to 13 hours.
• Kids your age (6-12 years old) — that's you — usually need about 9 to 12 hours of sleep each night. The exact amount depends on the kid. Some kids do great with 9, some need 11 or 12 [10].
• Teens (13-18) usually need about 8 to 10 hours. Teen body clocks shift later — that is real, not laziness — so teens often want to stay up later and wake up later, but they still need a lot of sleep.
• Grown-ups usually need about 7 to 9 hours.
• Older grown-ups (grandparents and up) sometimes sleep a little less, or sleep in different patterns. That is normal too.

These are RANGES, not exact numbers. The Cat is not going to tell you that you need exactly 10 hours. Your body knows what your body needs. Your trusted grown-ups help you figure out what works.

Every Body Has Its Own Sleep Story

The Cat wants to say one more thing before this lesson ends.

Some kids have bodies that handle sleep a little differently than other kids' bodies. Kids with health conditions, kids who take certain medicines, kids who use feeding tubes or other supports, kids whose brains work differently (the Turtle told you about neurodiversity at G4 — autism, ADHD, sensory differences) — many of these kids have their own sleep stories that work for them.

All of this is normal. The Cat does not compare one kid's sleep to another's. Some kids are early birds; some are night owls. Some kids fall asleep fast; some need quiet time. Some kids dream a lot; some rarely remember dreams. All of these are part of the wide variety of how humans sleep.

If your sleep looks different from your friend's, that is normal. If your sleep looks different from your sibling's, that is normal. Your trusted grown-ups know your body and your sleep. The Cat trusts them. So can you.

Lesson Check

1. Name the two parts of sleep the Cat introduced. What does each one do?
2. About how long is one full sleep cycle?
3. Why does deep sleep happen more in the first part of the night?
4. About how many hours of sleep do kids your age need each night?
5. Why does the Cat say sleep across ages is "biology, not personality"?

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Lesson 1.2: How Sleep Helps You

Learning Objectives

By the end of this lesson, you will be able to:

• Connect the Turtle's teaching about how your brain learns with the Cat's teaching about sleep
• Explain why "practice plus sleep" makes learning stick
• Name the day-night partnership between the Rooster (Coach Light) and the Cat (Coach Sleep)
• Name seven things that help most kids sleep well
• Notice your own sleep over a few days

Key Terms

The Cat and the Turtle Are Friends

The Cat and the Turtle work very closely. The Turtle's chapter, How Your Brain Works, just shipped — if you have read it, you remember the Turtle telling you about attention, memory, and practice. The Turtle taught you that:

• Attention lets information get into your brain.
• Memory holds onto things — short-term memory for a few seconds or minutes, long-term memory for years.
• Practice strengthens the connections in your brain so things stick.

That is all true. But here is the part the Cat wants to add — the part the Turtle hinted at but did not get to teach in full.

Practice during the day is just the first step. Sleep at night is what finishes the job.

When you practice something during the day, your brain builds a fresh connection. The connection is real, but it is still a little wobbly. It is in short-term form. If you went to bed and slept poorly, by the next morning a lot of what you practiced would have faded.

But if you sleep well, something magical happens at night. Your brain goes through its dream sleep parts, and during those parts, it takes the wobbly new connections from the day and saves them into long-term form. Grown-ups call this memory consolidation. The Cat just calls it "saving the work" [6, 11].

This is one of the most amazing things your body does. You go to bed knowing something halfway. You wake up knowing it more solidly. Your brain did real work while you slept. You did not have to do anything. Just be asleep.

The Bear (Coach Food) agrees. The Turtle (Coach Brain) agrees. The Cat agrees. Bodies, brains, and sleep are a team.

The Body Work of Sleep

The Cat already mentioned in Lesson 1 that deep sleep is when your body does its strongest work. Let me say more.

Growth hormones release during deep sleep. Growth hormones are tiny chemical messengers that tell your body to grow taller, build stronger muscles, repair tiny damage, and keep tissues healthy. Most of the day, your body releases only small amounts. But in deep sleep, your body releases big amounts [2, 3].

This is why doctors and scientists say sleep is important for growing kids. You are 9 or 10 — you are growing. Some kids your age grow several inches a year. That growing happens in the small slow hours of deep sleep, not during the day.

Your immune system rebuilds during deep sleep. The body's army that fights germs takes deep sleep as a chance to make new fighter cells, replace old ones, and get ready for the next day. Kids who consistently get too little sleep have a harder time fighting off germs. That is one reason why sick days come in batches — once your body is run down, it is harder to push back the next thing [4].

Your body cleans up tiny waste in your brain. This is one of the most surprising things scientists have learned in the last few years. While you sleep, special little channels in your brain open up, and the brain's wash system does a kind of nighttime cleanup. Things your brain made during the day that it does not need anymore — tiny waste products — get flushed away [12]. The Cat thinks this is amazing. Bodies are clever.

All of this happens while you are asleep, with your eyes closed, doing nothing. Just sleeping. Sleep is one of the most active things a body does.

The Brain Work of Sleep

Dream sleep — the part of the night the Cat told you about in Lesson 1 — is when your brain does its biggest work.

You already met the main job: saving what you learned. The Cat already explained this. But there are more brain jobs.

Settling feelings. Big feelings from the day get processed during dream sleep. A hard moment with a friend, a worry about a test, a sad memory — the brain works on these at night. This is one of the reasons a hard day often feels a little lighter in the morning. Your brain helped while you slept [13].

Making creative connections. During dream sleep, your brain plays with ideas. It connects things that did not seem connected during the day. Many writers, scientists, artists, and inventors say they get their best ideas after sleep. The Cat thinks this is one of sleep's quietest gifts — your brain making art while you rest.

Why dreams happen. Scientists are still studying exactly why we dream. The Cat will tell you what most scientists agree on at G4 depth: dreams are your brain doing its sorting and connecting work in the form of stories. Your brain takes pieces of your day, pieces of your memories, pieces of your feelings, and puts them together. The story can be normal or weird or funny or scary. Most dreams are not messages or predictions — they are just your brain doing its night work [14].

The Cat thinks of dreams like the steam coming off a pot of soup. The pot is busy. The steam is what you see. The cooking happens whether you watch the steam or not.

The Rooster and the Cat — Day-Night Partners

The Cat wants to say something the Cat said at G3 too, because it matters at G4 even more.

The Rooster and the Cat work as a team. The Rooster (Coach Light) handles the day side of your cycle. The Cat handles the night side. Together, we keep you running.

The Rooster's job is to teach you that light tells your body what time it is. Morning sunlight helps your body know it is daytime. Evening dim light helps your body know it is nighttime. The Cat's job is to teach you what happens during the night part.

If you read the Rooster's chapter at G3, Light and Your Body, you remember:

• Morning sunlight helps you wake up alert and helps you sleep better that night.
• Bright screens close to bedtime can confuse your body's clock.
• Your body has a clock that follows the sun.

All of that is still true at G4. The Cat fully agrees. Light during the day and dark at night keep your body's clock running well, which keeps sleep coming on time. The Rooster and the Cat are partners. We tell the same story from two sides.

Seven Things That Help Most Kids Sleep Well

At G3, I told you four things that help most kids sleep. Those four are still true at G4. I am going to repeat them and add three more for G4.

The four from G3:

1. A calm bedtime routine. The same calm steps each night — toothbrush, pajamas, story or quiet talk, hug, lights out. Bodies love routines because routines tell the body "sleep is coming."

2. A dark, cool, quiet sleeping place. Dark helps your body's clock. Cool helps your body settle. (Your body lowers its temperature a little to sleep, so a cool room helps.) Quiet helps your brain stop scanning the world. None of these have to be perfect. Many kids sleep with a little nightlight, a fan running, or with siblings in the room — all fine.

3. Similar bedtimes and wake times most days. Going to bed and waking up at about the same time each day — including weekends — keeps your body's clock steady. Big weekend shifts (staying up super late on Saturday, sleeping until noon Sunday) can confuse the clock. Some flexibility is fine, but big shifts make Monday morning harder.

4. Dim light and no screens close to bedtime. Bright screens (phones, tablets, TVs) close to bedtime can trick your body's clock into thinking it is still day. The Rooster and the Cat both agree. Your trusted grown-ups decide what works for your family.

The three G4 additions:

1. Moving during the day. Bodies that move during the day sleep better at night. The Lion (Coach Move) told you about this in Moving and Your Body — moving is one of the best things for sleep. Even on a busy school day, twenty minutes of real play, walking, or movement makes a difference [15].

2. Eating real food, and not too much sugar close to bedtime. The Bear and I agree on this. Real food (vegetables, fruits, protein, healthy fats — all the things the Bear taught about) helps your body and brain do their night work. A big sugar load close to bedtime can make falling asleep harder for some kids. Your trusted grown-ups know your body.

3. Having a way to settle worries before bed. This is the G4 addition the Cat thinks is most important. Many kids your age — 9, 10, 11 — start having more worries at bedtime. School, friendships, family changes, things they saw on a screen. The worries pop up just when you are trying to sleep. The Cat suggests one or both of these:

   • A worry-jar or worry-paper. Before bed, write down or draw the worries you are carrying. Put them in a jar, a notebook, a special drawer. The act of putting them down often quiets them.
   • A bedtime grown-up talk. Tell a trusted grown-up about the worries before lights-out. Many parents and caregivers love this — they get to know what is on their kid's mind, and you get the relief of being heard.

The Cat will say more in Lesson 3 about when worries get too big for these simple practices. For now, just know: worries are a normal part of being a kid at your age, and there are gentle ways to handle them at bedtime.

A Week of Sleep-Noticing

Here is what the Cat wants you to try.

Pick this week — any normal school week — to notice your sleep. Each morning when you wake up, just notice three things:

• About what time did I go to bed?
• About what time did I wake up?
• How do I feel right now — rested, sleepy, in between?

You do not have to write it down (though you can — the end-of-chapter activity will). Just notice.

By the end of the week, you may see patterns. Maybe Wednesdays feel groggier — and you realize you stayed up Tuesday on a screen. Maybe Saturday mornings feel great — and you realize you went to bed at your usual time the night before. The Cat watches these patterns all the time. Once you start watching yours, you will see them too.

Lesson Check

1. The Cat and the Turtle agree: practice during the day plus sleep at night equals what?
2. Name two things your body does during deep sleep.
3. The Rooster and the Cat are partners. What does each one handle?
4. Name three of the seven things that help most kids sleep well.
5. What is a "worry-jar"?

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Lesson 1.3: When Sleep Is Hard

Learning Objectives

By the end of this lesson, you will be able to:

• Tell the difference between an occasional hard night and a pattern of hard sleep
• Name four patterns that should be talked about with a trusted grown-up
• Notice that sleep changes can be a signal that something else is going on
• Understand why the Cat and the Turtle work closely on this
• Know what to do if a feeling at bedtime ever feels really scary or unsafe

Key Terms

The Cat Is Going to Be Honest

The Cat is going to be honest with you, like the Cat was at G3 but a little more deeply.

Most kids have hard sleep nights sometimes. You did. You will. Every kid does. Every grown-up does. Every cat does (yes — even cats have nights where they cannot settle). An occasional hard night is just part of being alive.

The Cat is not worried about an occasional hard night. The Cat IS interested in patterns — when sleep is hard for many nights in a row, or in the same way over and over.

At G3 I told you: when sleep is hard for many nights, or when feelings get big at bedtime, you tell a trusted grown-up. That is still true at G4. The Cat just wants to add something the Turtle told you about in How Your Brain Works.

Sleep changes are often a signal that something else is going on.

When kids your age start having a lot of trouble sleeping, it is often connected to feelings, worries, or things happening in their life. Sleep and how-you-feel are deeply connected. The Cat and the Turtle work very closely on this — neither of us can do our job well if the other is struggling.

Patterns Worth Telling a Grown-Up About

The Cat has a list. These are patterns — not single bad nights, but things that keep happening over a week or two.

If any of these are happening to you, please tell a trusted grown-up.

1. Trouble falling asleep almost every night. You lie in bed for a long time. Your brain will not stop. Maybe you watch the clock. Maybe you feel restless. Maybe you finally fall asleep an hour or two after lights-out, most nights. Tell a grown-up.

2. Waking up many times during the night. Some night-waking is normal — most people briefly wake up several times each night and barely remember. But if you fully wake up many times, with worries or thoughts or just-not-being-able-to-go-back-to-sleep — that is a pattern.

3. Bad dreams that keep coming back. Single bad dreams are normal — every kid has them. The pattern to watch for is the same dream or similar themes coming back over and over, especially if the dreams are scaring you out of sleep or making you not want to go to bed.

4. Feeling tired during the day even after what should be a full night. You went to bed on time. You "slept" for ten hours. But you feel tired anyway — yawning at school, struggling to focus, wanting to lie down in the afternoon. Something is off. Tell a grown-up.

5. Not wanting to go to bed. This one is important. The Cat is NOT talking about "I want to stay up later because the show is good." The Cat is talking about not wanting to go to bed because something about bed feels scary or sad or wrong. Kids who are scared of bedtime, or who feel really sad as bedtime approaches, are telling us something.

6. Feeling sleepy at school regularly. Once in a while is normal. Most days is a pattern.

7. Sleep changes that come with feeling changes. This is the deepest pattern. When sleep gets harder around the same time other things get harder — feeling sadder, more worried, more alone, less interested in things you used to love — that is the Cat and the Turtle both paying attention. Cross-reference G4 Brain Lesson 3 — the Turtle named these patterns too.

8. A friend or sibling showing any of these patterns. You can tell a grown-up about someone else, too.

The Cat is firm about this. These are not diagnoses. The Cat is not a doctor. The Cat is not going to tell you that any of these means a specific thing. The Cat is telling you they are patterns worth a conversation — with your trusted grown-up, with your doctor if your grown-up thinks that's right, with a school nurse, with whoever can help.

Why The Cat and The Turtle Work Closely

In the Turtle's chapter (How Your Brain Works), the Turtle told you that some kids at your age start having harder feelings — worry that keeps coming back, sadness that does not lift in a few days, feeling alone with others, body aches with worries, wanting to hide. The Turtle named these as patterns to tell a trusted grown-up about.

The Cat is going to tell you something the Cat and the Turtle agreed on quietly behind the scenes:

Hard sleep often comes with those feelings. Settling feelings often comes with better sleep. They go together. When the Turtle's patterns show up, the Cat's patterns often show up too. And when one gets help, the other often improves.

This is why a grown-up's first question when sleep is hard is often: "How are you feeling?" Not because they are nosy. Because they know what the Cat and the Turtle know — these two parts of you are connected.

If you go to a trusted grown-up about hard sleep, expect them to ask about your feelings too. That is them being a good grown-up. Tell them what is true. You are not alone with any of this.

Who Are Trusted Grown-Ups

You learned this term at G3, and the Turtle reinforced it at G4. The Cat says it again because some lessons matter enough to say nine times.

A trusted grown-up is a grown-up who:

• Takes care of you
• Knows you
• Loves you
• Wants what is good for you
• Listens when you talk
• Helps when something is hard

For most kids, trusted grown-ups include:

• A parent, step-parent, or guardian
• A grandparent
• A foster parent or other caregiver
• An aunt, uncle, or older family member
• A teacher you trust
• A school counselor
• A school nurse
• Your doctor or pediatrician
• A coach or religious leader you trust

Take a slow moment right now. In your head, name two trusted grown-ups you could tell about hard sleep or hard feelings. Just think their names.

The Cat is glad you thought of them.

When a Feeling at Bedtime Feels Really Scary or Unsafe

The Cat is careful here.

At G3, I told you that if a feeling at bedtime feels really scary or unsafe, you tell a trusted grown-up right away. That is still true at G4. The Cat will say it again because it matters.

Sometimes — at any age, but more often as kids get older — a feeling can get really big. Maybe at bedtime, when the lights are off and the day's noise has stopped, your worries grow louder. Maybe a feeling tells you that you do not want to be here anymore. Maybe a feeling makes you want to hurt yourself.

If a feeling like that ever comes up — tell a trusted grown-up right away. Not later. Right then. Even if it is the middle of the night. Even if you think they will be worried. They will not be mad. They will be glad you told them. Telling a trusted grown-up about a really scary feeling is one of the strongest things a kid can do.

If you cannot reach a trusted grown-up at that moment, here are special phone numbers grown-ups can use when feelings get really scary or unsafe. The Cat wants you to know they exist. You do not have to remember the numbers — the grown-ups in your life can use them.

• The 988 Suicide and Crisis Lifeline: a grown-up can call or text 988, any time of day or night. Real people answer. They help right away.
• Crisis Text Line: a grown-up can text HOME to 741741, any time of day or night. Real people answer by text.
• SAMHSA National Helpline: 1-800-662-4357, day or night, for any kind of big worry.
• National Alliance for Eating Disorders: 866-662-1235, weekdays. The Bear told you about this one in G4. It is for grown-ups when worries are about food, eating, or how a kid feels about their body.

These helpers are for grown-ups to use when you and they need them. Kids your age do not call helplines on their own. You tell a trusted grown-up first. The grown-up takes care of the rest.

The Bear, the Turtle, the Cat — and the other six Coaches you met at G3 — are all saying the same thing. We agree. You are not alone with hard sleep or hard feelings. Not now, not ever.

Sleep Is a Friend

The Cat will end this chapter the way the Cat ended the G3 chapter, because the message has not changed. Sleep is a friend. Not a punishment. Not a thing you are missing. Not wasted time.

Sleep is one of the most important parts of your life. Sleep is when your body grows. Sleep is when your brain saves what you learned. Sleep is when your feelings settle. Sleep is when your wash system flushes out the day. Sleep is the slow, quiet, deep work of being alive.

The Cat watches over your sleep. The Rooster watches over your day. The Bear watches over your food. The Turtle watches over your brain. The Lion watches over your moving. The Penguin watches over the cold. The Camel watches over the heat. The Dolphin watches over your breath. The Elephant watches over your water.

That is nine of us. All on your team. All in your corner.

The Cat will see you again at Grade 5. There is more to learn then. For now, this is enough.

The Cat is calm. The Cat is patient. Take a slow breath. Begin. Quietly.

Lesson Check

1. What is the difference between an occasional hard night and a pattern?
2. Name three patterns the Cat says you should tell a trusted grown-up about.
3. Why does the Cat say "sleep changes are often a signal that something else is going on"?
4. The Cat and the Turtle work closely on this. Why?
5. If a feeling at bedtime ever feels really scary or unsafe, what is the FIRST thing the Cat says you should do?

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End-of-Chapter Activity: A Week of Sleep Noticing

The Cat has one activity for you. It takes one week and a little bit each day. You can start any day.

What You Need

• A piece of paper or a small notebook
• A pencil
• One normal week of your life
• A trusted grown-up to share with at the end

What You Do

Step 1 — Make a sleep sheet (Day 1). At the top of your paper, write the week's dates. Below, make a small chart with seven rows (one per day) and four columns:

• Bedtime (about what time did I go to bed?)
• Wake time (about what time did I wake up?)
• How I felt waking up (rested? sleepy? in between?)
• One thing (a dream I remembered, a worry that came up at bedtime, anything that stood out — one sentence is plenty)

Step 2 — Fill it in each morning. Each morning of the week, take two minutes and fill in your row. Best guess is fine — you do not need exact times. Be honest. Nobody is going to grade this.

Step 3 — Notice patterns by the end of the week. Read over your sheet. Ask yourself:

• Did some bedtimes work better than others?
• Did some wake times feel better than others?
• Were there nights I felt worried at bedtime? What happened those nights?
• Did I dream often? Rarely?
• What was my best morning of the week? My hardest?

Step 4 — Share with a trusted grown-up. Show your sheet to a trusted grown-up. Tell them what you noticed. Ask them one of these:

• What does your sleep look like during the week?
• Do you have a bedtime worry sometimes?
• What helps you sleep well?

Listen to their answer. Many grown-ups have thought about their sleep more than kids think they have.

Step 5 — Keep the sheet. Save it. The Cat thinks sleep noticings are interesting to look back on. Some kids keep a quiet sleep notebook for a while and add to it. Some keep just one week. Both are fine.

What You Will Get From This

You will start to see your own sleep — really see it — in a way most kids never do. You will notice that some nights work better than others. You will start to learn what helps your body sleep. And you will share something small with a grown-up who loves you.

That is a small habit. It is also a big skill. The Cat thinks both are true.

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Vocabulary Review

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Chapter Review

These questions are not a test. They are a way to check what you remember. Take your time. Look back at the lessons if you need to. There are no tricks.

1. Name the two parts of sleep the Cat introduced. What does each one do?

2. About how long is one full sleep cycle? About how many cycles happen in a 9-hour night?

3. The Turtle teaches that practice strengthens connections. The Cat teaches what happens at night. Together, what makes learning stick?

4. Name three of the seven things that help most kids sleep well.

5. What is a pattern in sleep, and what should you do about one?

6. If a feeling at bedtime ever feels really scary or unsafe, what should you do?

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Instructor's Guide

This guide is for parents, caregivers, teachers, and other grown-ups using this chapter with a child in Grade 4 (ages 9-10).

What This Chapter Teaches

This chapter is the second chapter in Coach Sleep (the Cat)'s K-12 spiral and the third chapter of the Grade 4 cycle. It builds directly on the Grade 3 chapter Your Sleep and You and the just-shipped G4 Brain chapter How Your Brain Works. The chapter teaches three big ideas at age-appropriate Grade 4 depth:

1. How sleep actually works. Sleep has different parts. At Grade 4 the parts are named by job: deep sleep (body work — growth, repair, immune rebuilding) and dream sleep (brain work — sorting, saving, settling feelings, dreaming). The technical names (REM, NREM) wait for Grade 6. The cycle concept is introduced more concretely than at G3 — about 90 minutes per cycle, with early cycles heavy on deep sleep and late cycles heavy on dream sleep — without making kids do the math (G6 territory). The chapter introduces "sleep across life" descriptively: babies sleep most, kids 6-12 need 9-12 hours, teens need 8-10, adults 7-9, older adults sometimes less.

2. How sleep helps you. The deepest cross-tier connection in this chapter: the Cat and the Turtle work together. The Turtle's just-shipped chapter taught that practice strengthens brain connections; the Cat adds that sleep is when those connections get saved (memory consolidation). The full sleep-and-body story is told at G4 depth — growth hormones during deep sleep, immune rebuilding, brain waste cleanup, feelings settling, creative connections. The Rooster/Cat day-night partnership from G3 is reinforced. Seven sleep helpers are named: the G3 four (calm routine, dark/cool/quiet place, similar times, dim light/no screens close to bedtime) plus three G4 additions (moving during the day, real food / no big sugar close to bedtime, worry-jar or grown-up talk to settle worries).

3. When sleep is hard. This is the safety-critical lesson. Builds on G3's framework with eight specific patterns to tell a trusted grown-up about — explicitly framed as patterns (multiple nights in a similar way), not diagnoses. The chapter introduces the key G4 insight that sleep changes are often a signal that something else is going on — sleep and mental health are deeply linked. The Cat and Turtle partnership is named explicitly: when one of these struggles, the other often does too. Mental health vigilance is heightened from G3, matching G4 Brain's heightened framing for ages 9-10 entering the developmental window for emerging anxiety/depression. Crisis resources are introduced at age-appropriate framing.

What This Chapter Does NOT Teach

This chapter is intentionally light on content that becomes appropriate at later grades:

• No REM/NREM technical naming. Stages are named by job (deep sleep, dream sleep) only. REM and NREM arrive at Grade 6.
• No hypnograms. Grade 6 introduces the visual sleep-stage chart.
• No exact cycle math (90 minutes × 6 cycles = 540 minutes; Maya's bedtime example). Grade 6 covers this.
• No SCN, melatonin, adenosine technical vocabulary. Grade 8 territory.
• No clinical sleep disorder names (insomnia, sleep apnea, narcolepsy). The chapter teaches the patterns to notice but routes any specific concern to trusted grown-ups and doctors.
• No prescriptive sleep amounts. The 9-12 range is presented descriptively, with explicit acknowledgment that some kids do well with 9, some need 11 or 12, and individual needs vary.

If your child asks questions in these areas, the best answer is: "That is a great question. Let's figure it out together." Then you, the trusted grown-up, decide what to share.

How to Support the Child

A few things you can do that align with the chapter's framing:

• Honor bedtime as something important, not just an end-of-day chore. Children at ages 9-10 are increasingly aware of their own choices. Help them connect bedtime to how they will feel tomorrow.
• Build a calm wind-down. Even 20 minutes of dimmer light, slower pace, and one or two predictable routine steps (toothbrush, pajamas, story or quiet talk) supports the body's transition to sleep.
• Be the bedtime worry-talker. The chapter introduces the worry-jar and the bedtime grown-up talk as G4 additions to the G3 four supports. Many kids at ages 9-10 start having more worries at bedtime; you offering to hear them, briefly, before lights-out can settle the brain in a way nothing else can.
• Watch the cycles together. The chapter teaches that mornings near a dream-sleep wake-up sometimes feel groggier than mornings near a lighter-sleep wake-up. Talking about how mornings feel — without judgment — builds your child's awareness of their own sleep.
• Protect screens before bed. The chapter reinforces the G3 message: bright screens close to bedtime trick the body's clock. Your family decides specifics; protecting the last 30-60 minutes before bed is a strong general practice.
• Take sleep complaints seriously. If your child reports trouble falling asleep, frequent night-waking, recurring bad dreams, or daytime tiredness for more than a couple of weeks, treat the pattern as worth a conversation — possibly with your pediatrician.

Watching for Warning Signs

Children at ages 9-10 are entering the developmental window where anxiety, depression, and sleep difficulties often appear together. The chapter is preventive. If you notice any of the following for more than two to three weeks, please contact your pediatrician or a qualified clinician:

• Persistent trouble falling asleep or staying asleep
• Daytime sleepiness despite adequate time in bed
• Recurring nightmares or bedtime resistance with distress
• Loud snoring, pauses in breathing, or gasping during sleep (these warrant evaluation for sleep-disordered breathing)
• Sleep changes that appear alongside mood changes — sadness, withdrawal, increased worry, lost interest in former favorites
• Frequent body complaints (stomachaches, headaches) clustered around bedtime or school mornings
• Any mention of not wanting to be here, wanting to hurt themselves, or feeling hopeless — these require immediate response, day or night

Verified resources (May 2026):

• 988 Suicide and Crisis Lifeline: call or text 988, 24/7. The right first call for any mention of suicide or self-harm.
• Crisis Text Line: text HOME to 741741, 24/7.
• SAMHSA National Helpline: 1-800-662-4357, 24/7. General mental health and substance use referrals.
• National Alliance for Eating Disorders: 866-662-1235, weekdays. Licensed therapists. Particularly relevant if sleep issues appear alongside eating or body-image concerns.
• Your pediatrician is the best starting place for any persistent sleep concern. For sleep-disordered breathing, a referral to a pediatric sleep specialist may be appropriate.

Note: the NEDA helpline (1-800-931-2237) is not functional as of this writing. Use the National Alliance for Eating Disorders number above instead.

Pacing

If you are using this chapter in a classroom:

If you are using this chapter at home, two lessons per week is comfortable. The end-of-chapter activity is a one-week project. Lesson 3 may benefit from being read alongside a trusted grown-up rather than alone — both because the mental-health content matters and because it explicitly invites a family conversation about sleep and feelings.

Lesson Check Answers

Lesson 1.1:

1. Deep sleep (body work — growth, repair, immune rebuilding) and dream sleep (brain work — sorting, saving learning, settling feelings, dreaming). 2. About 90 minutes. 3. Because the body's biggest repair-and-growth work happens then, and the body schedules that work for the first part of the night. (Also: most deep sleep is built into the first 2-3 cycles of the night.) 4. 9 to 12 hours, with some variation between kids. 5. Because bodies and brains genuinely change as we grow — newborns need way more sleep than adults, kids need more than adults, teen body clocks shift later for real biological reasons. It is not about being lazy or hardworking; it is about what the body needs at each stage.

Lesson 1.2:

1. Learning that sticks. (Practice during the day + sleep at night = saved learning.) 2. Any two of: growth hormones release, immune system rebuilds, body repairs muscles/scrapes, brain waste cleanup. 3. The Rooster handles the day side of the cycle (light, body clock setting). The Cat handles the night side (sleep itself). 4. Any three of: calm bedtime routine, dark/cool/quiet sleeping place, similar bedtimes and wake times, dim light/no screens close to bedtime, moving during the day, real food / no big sugar close to bedtime, settling worries before bed. 5. A way to put worries down before bed — by writing or drawing them on paper, or putting them in a jar, or telling a trusted grown-up. The act of putting them down often quiets them.

Lesson 1.3:

1. An occasional hard night happens to everyone — one bad night, a worry, a bad dream — and is part of being alive. A pattern is when hard sleep keeps happening, in similar ways, over a week or two — that is what to tell a trusted grown-up about. 2. Any three of: trouble falling asleep almost every night, waking many times with trouble going back, recurring bad dreams, feeling tired during the day, not wanting to go to bed (out of fear/sadness), feeling sleepy at school, sleep changes alongside feeling changes. 3. Because sleep and feelings are deeply connected. When kids are struggling with worry, sadness, or other big feelings, sleep often suffers too. The Cat and the Turtle work closely on this — neither can do their job well if the other is struggling. 4. Because sleep and mental health are deeply connected. When one struggles, the other often does too. When one gets help, the other often improves. 5. Tell a trusted grown-up right away. The grown-up can call 988 or another helpline if needed.

Chapter Review Answers

1. Deep sleep (body work) and dream sleep (brain work). 2. About 90 minutes per cycle. About 6 cycles in a 9-hour night. 3. Learning that sticks (saved into long-term memory). 4. Any three from Lesson 2's list of seven. 5. A pattern is something that happens more than once, in a similar way. Tell a trusted grown-up about the pattern. 6. Tell a trusted grown-up right away. The grown-up can call a doctor, 988, or another helpline if needed.

Discussion Prompts

Open-ended questions to ask the child after the chapter:

1. About what time did you go to bed last night? How did you feel waking up?
2. Do you remember a dream lately? What was it like?
3. The Cat says sleep is when your brain saves what you learned. Is there something you practiced this week that feels easier now than at the start of the week?
4. What does your bedtime routine look like? Is there anything you wish were different?
5. Who is the trusted grown-up you would talk to first about hard sleep?
6. The Rooster handles the day. The Cat handles the night. What is one thing they agree on?
7. Have you ever had a worry that came up just at bedtime? What happened with it?
8. The Cat says sleep is a friend, not a punishment. Does it feel like that to you? Why or why not?

Common Child Questions

• "Why do I dream weird things?" Your brain is sorting through pieces of your day, your feelings, and your memories during dream sleep. It puts them together in odd ways. The Cat thinks of dreams as your brain doing its work in the form of stories. Most dreams are not messages or predictions — just brain activity.
• "Why don't I remember most of my dreams?" Most dreams fade quickly once you wake up. Some people remember more dreams than others. There is nothing wrong with not remembering — your brain still did its work.
• "My friend says they only need six hours of sleep. Is that true?" Probably not for a kid your friend's age. Some adults can function on less sleep, but kids your age really do need 9-12 hours. Sometimes kids say things they hear adults say, even when it does not match what their bodies actually need. Trust the research, not the brag.
• "Why do I feel groggy in the morning sometimes even after a long sleep?" You may have woken up in the middle of a deep-sleep part of a cycle, which makes grogginess. Different cycles end at different times. The Cat does not worry about occasional grogginess.
• "Is it bad if I stay up late sometimes?" Occasional late nights are fine. What matters is the overall pattern. Most nights at a similar time, with enough sleep, is what bodies and brains need. Special-occasion late nights are normal.
• "Why do I have bad dreams sometimes?" Bad dreams are normal and happen to everyone. The Cat is more concerned about a pattern of bad dreams that keeps coming back, especially with similar themes or that scare you out of sleep regularly. Single bad dreams are part of being a person.
• "I'm scared of bedtime. What do I do?" Tell a trusted grown-up. Fear of bedtime is real and is the kind of pattern the Cat takes seriously. There are many things that can help — a different routine, a nightlight, time with a grown-up before bed, sometimes a doctor's help. You are not alone in this.
• "Can I make up for bad sleep by sleeping in on weekends?" A little. But big weekend shifts confuse your body's clock and make Monday harder. The Cat recommends keeping bedtimes and wake times within about an hour of usual, even on weekends. Naps can help fill in occasional gaps.
• "What if I dream the same scary dream over and over?" Tell a trusted grown-up. Recurring dreams are one of the patterns the Cat watches. They are often connected to something your brain is working through, and a grown-up can help.

Parent Communication Template

Dear families,

Your child is beginning Chapter 1 of the Grade 4 CryoCove Library Coach Sleep curriculum — How Sleep Works. This is the second chapter in Coach Sleep (the Cat)'s K-12 spiral, building on the Grade 3 chapter Your Sleep and You. It also builds on the just-shipped Grade 4 Brain chapter, How Your Brain Works.

What the chapter covers:

• That sleep has different parts — deep sleep (body work) and dream sleep (brain work) — and these parts cycle through the night
• About 90 minutes per cycle, with early cycles heavy on deep sleep and late cycles heavy on dream sleep
• Why dreams happen (the brain sorting through the day)
• How sleep needs change across life (newborns to older adults)
• The Cat and the Turtle partnership: practice during the day + sleep at night = learning that sticks
• Seven things that help most kids sleep well — the G3 four plus three G4 additions (moving during the day, real food without too much sugar close to bed, settling worries before bed with a worry-jar or grown-up talk)
• Eight specific patterns of hard sleep that warrant a conversation with a trusted grown-up

Tone: The chapter is calm, slow-moving, and patient — the Cat's signature voice. The Cat acknowledges that your child has met the Cat before at Grade 3 and is now ready for a slightly deeper conversation. The chapter never compares one child's sleep to another, never frames sleep as moral or willpower-based, and is consistently inclusive of different family bedrooms, sleeping arrangements, and conditions affecting sleep.

What this chapter does not teach: technical sleep architecture (REM, NREM, hypnograms — Grade 6), exact cycle math, clinical sleep disorder vocabulary (insomnia, sleep apnea — those route to pediatricians), or prescriptive sleep amounts. The 9-12 hour range is presented descriptively, with individual variation explicitly named.

End-of-chapter activity: Your child will spend a week noticing their sleep — bedtime, wake time, how they feel waking up, and one notable thing each morning — and share with a trusted grown-up at the end. Please support this. The lived experience of seeing your own sleep patterns is one of the chapter's most important takeaways.

A note on Lesson 3: Lesson 3 covers when sleep is hard and explicitly introduces the G4 insight that sleep changes are often a signal that something else is going on. The Cat and the Turtle (Coach Brain) work closely on this — sleep and mental health are deeply linked, and many of the patterns named in Lesson 3 (trouble falling asleep, recurring bad dreams, sleep changes alongside feeling changes) can be early signals of emerging anxiety or depression in children at ages 9-10. The chapter handles this preventively, without clinical labels, and routes patterns firmly to trusted grown-ups. Crisis resources (988, Crisis Text Line — text HOME to 741741, SAMHSA, National Alliance for Eating Disorders) are introduced at age-appropriate "grown-ups can call these if you need help" framing. If you would like to read Lesson 3 alongside your child, that is welcome.

Warning signs we ask families to notice: persistent trouble falling or staying asleep, daytime sleepiness despite adequate time in bed, recurring nightmares with distress, sleep changes alongside mood changes, frequent body complaints clustered around bedtime, loud snoring or breathing pauses, and any mention of not wanting to be here. If you notice any of these for more than two to three weeks, please contact your pediatrician. Verified resources are listed in the Instructor's Guide section of the chapter.

If you have any questions, please reach out to your child's teacher or to us at the CryoCove team.

Warmly, The CryoCove Curriculum Team

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Illustration Briefs

Lesson 1.1 — Sleep Has Parts Placement: After "The Cat Watches Again." Scene: A soft, peaceful nighttime scene showing a child asleep in their bed. Above the child, a gentle dotted line shows a "wave" — going down to a dark blue band labeled "Deep sleep — body works," coming back up partway, going down again to another deep blue band, then up to a lighter blue band labeled "Dream sleep — brain works," then back down, and so on. The line forms three or four soft waves across the picture from sundown to sunrise, with a small moon at the start and a small sun rising at the end. Coach Sleep (the Cat) is curled up at the foot of the bed, eyes half-closed but watchful. Mood: peaceful, gentle, never spooky, never medical-diagram. Show diverse skin tones throughout the chapter's illustrations. Aspect ratio: 16:9 web, 4:3 print.

Lesson 1.2 — Seven Sleep Helpers Placement: After "Seven Things That Help Most Kids Sleep Well." Scene: A simple seven-panel illustration showing the seven sleep helpers. Each panel has a small scene: 1) a child brushing teeth and putting on pajamas (calm routine); 2) a softly dim bedroom with a kid being tucked in (dark, cool, quiet); 3) a clock and calendar showing similar times each day (similar bedtimes/wake times); 4) a phone and tablet sitting in a basket on a shelf far from a bed (no screens close to bedtime); 5) a kid playing tag outside in afternoon light (move during the day); 6) a family at a kitchen table eating a normal dinner (real food); 7) a kid sitting up in bed with a small notebook, drawing a worry, while a trusted grown-up sits nearby (worries settled). Coach Sleep (the Cat) curls up at the bottom edge of the illustration, eyes half-closed, looking pleased. Mood: warm, ordinary, peaceful. Show diverse skin tones and family settings across the chapter. Aspect ratio: 16:9 web, 4:3 print.

Lesson 1.3 — A Trusted Grown-Up at Bedtime Placement: After "Patterns Worth Telling a Grown-Up About." Scene: A simple, warm, quiet scene. A child is sitting up in bed in soft lamp light, looking a little tired, with a slight frown — not crying, not in distress, just looking worn down. A trusted grown-up sits on the edge of the bed, body turned toward the child, listening. The grown-up has a calm, attentive face — not on a phone, not distracted. One of the grown-up's hands is resting on the bed near the child's. A glass of water on the bedside table, a small night light, a soft blanket. Coach Sleep (the Cat) is curled at the foot of the bed, eyes half-open. Small text near the scene reads: "When sleep stays hard, telling a trusted grown-up is the strongest thing a kid can do." Mood: safe, calm, warm, never bleak. Show diverse skin tones. Aspect ratio: 16:9 web, 4:3 print.

Optional — Lesson 1.2: The Cat and the Rooster Placement: After "The Rooster and the Cat — Day-Night Partners." Scene: A simple split-scene image. Left half: morning, golden light, a Rooster perched on a fence facing the sunrise, a child waking and stretching in a sunlit bedroom in the background. Right half: evening, soft twilight, the same Rooster now asleep on a low perch with eyes closed, a Cat sitting alert and watching over a child who is winding down for bed in lamp light. A vertical line in the middle of the picture connects the two halves — labeled simply "Day — Rooster's watch / Night — Cat's watch." Mood: peaceful, complementary, never split or oppositional — these are two parts of one whole cycle. Show diverse skin tones. Aspect ratio: 16:9 web, 4:3 print.

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Citations

1. Carskadon, M. A., & Dement, W. C. (2017). Normal human sleep: an overview. In M. H. Kryger, T. Roth, & W. C. Dement (Eds.), Principles and Practice of Sleep Medicine (6th ed., pp. 15-24). Elsevier.

2. Takahashi, Y., Kipnis, D. M., & Daughaday, W. H. (1968). Growth hormone secretion during sleep. Journal of Clinical Investigation, 47(9), 2079-2090.

3. Van Cauter, E., Spiegel, K., Tasali, E., & Leproult, R. (2008). Metabolic consequences of sleep and sleep loss. Sleep Medicine, 9 Suppl 1, S23-S28.

4. Besedovsky, L., Lange, T., & Haack, M. (2019). The sleep-immune crosstalk in health and disease. Physiological Reviews, 99(3), 1325-1380.

5. Aserinsky, E., & Kleitman, N. (1953). Regularly occurring periods of eye motility, and concomitant phenomena, during sleep. Science, 118(3062), 273-274.

6. Walker, M. P., & Stickgold, R. (2006). Sleep, memory, and plasticity. Annual Review of Psychology, 57, 139-166.

7. Stickgold, R. (2005). Sleep-dependent memory consolidation. Nature, 437(7063), 1272-1278.

8. Iber, C., Ancoli-Israel, S., Chesson, A. L., & Quan, S. F. (2007). The AASM Manual for the Scoring of Sleep and Associated Events. American Academy of Sleep Medicine.

9. Hirshkowitz, M., Whiton, K., Albert, S. M., Alessi, C., Bruni, O., DonCarlos, L., Hazen, N., Herman, J., Katz, E. S., Kheirandish-Gozal, L., Neubauer, D. N., O'Donnell, A. E., Ohayon, M., Peever, J., Rawding, R., Sachdeva, R. C., Setters, B., Vitiello, M. V., Ware, J. C., & Adams Hillard, P. J. (2015). National Sleep Foundation's sleep time duration recommendations: methodology and results summary. Sleep Health, 1(1), 40-43.

10. Paruthi, S., Brooks, L. J., D'Ambrosio, C., Hall, W. A., Kotagal, S., Lloyd, R. M., Malow, B. A., Maski, K., Nichols, C., Quan, S. F., Rosen, C. L., Troester, M. M., & Wise, M. S. (2016). Recommended amount of sleep for pediatric populations: a consensus statement of the American Academy of Sleep Medicine. Journal of Clinical Sleep Medicine, 12(6), 785-786.

11. Tarokh, L., Saletin, J. M., & Carskadon, M. A. (2016). Sleep in adolescence: physiology, cognition and mental health. Neuroscience and Biobehavioral Reviews, 70, 182-188.

12. Xie, L., Kang, H., Xu, Q., Chen, M. J., Liao, Y., Thiyagarajan, M., O'Donnell, J., Christensen, D. J., Nicholson, C., Iliff, J. J., Takano, T., Deane, R., & Nedergaard, M. (2013). Sleep drives metabolite clearance from the adult brain. Science, 342(6156), 373-377.

13. Goldstein, A. N., & Walker, M. P. (2014). The role of sleep in emotional brain function. Annual Review of Clinical Psychology, 10, 679-708.

14. Mindell, J. A., & Owens, J. A. (2015). A Clinical Guide to Pediatric Sleep: Diagnosis and Management of Sleep Problems (3rd ed.). Wolters Kluwer.