Sleep

We spend about one third of our life sleeping!

Why do we sleep? No one really knows…but

• Inactivity theory: Moving around at night is dangerous.

• Saving energy theory: Moving around uses energy, so we don’t need to eat as much if we sleep.

• Body repair theory: The body repairs itself when we sleep.

• Brain plasticity theory: The brain is very complicated, and may need sleep to help it stay organized.

How long should you sleep every night?

• We should sleep between 7 and 9 hours every night.

The sleep cycle

REM sleep is the best for your body.

Circadian rhythms

snoring

Snoring is loud and annoying. Do you snore?

Sleep apnea

Makes people wake in the night because they can’t breathe. It is scary, dangerous and unhealthy.

insomnia

People with insomnia have trouble sleeping.

Stress and caffeine can cause insomnia.

Don’t drink caffeine in the afternoon or evening.

The world record for the longest time without sleep is 11 days!

In which picture do you think she hasn’t slept?

Insomnia is bad for you.

sleepwalkingPeople usually don’t remember when they do this.

Sometimes they do dangerous things like driving a car or cooking.

Alcohol and stress can cause sleepwalking.

Driving while tired is as bad as driving drunk.

Eating before bedtime.

Acid reflux

When you are lying down, acid from your stomach can come up to your mouth. Not fun.

Not enough sleep can make you fat!

• Not getting enough sleep raises your cortisol, and makes you feel hungry all the time. It also makes your body store fat.

Sleeping pills

• Medicines like hydroxymine can help you sleep, but we should only use them when we really need them.

Working shifts

Working at irregular times can mess up our sleep.

This is bad for us.

Taking a nap

Taking a 25 minute nap can be refreshing.

But napping too much can be bad for you.

Nightmares and dreams

Babies sleep a lot!

• Babies sleep between 10.5 and 18 hours per day. They need it for their brain to develop.

Exercise helps us sleep

Sleep has changed over time

• A long time ago, people slept when it was dark, and slept 2 or 3 times every day.

Jet lag

• If you travel to faraway countries you will probably have jet lag because of the change in time zones.

A snail can sleep for three years!

Sea otters hold hands when they sleep so they don’t separate.

Questions• What percent of our life do we spend

sleeping?• What are some things that can help us sleep?• What is a bad dream called?• When do we get “jet lag”?• What is it called when we can’t sleep?• How long should we sleep every night?• What is it called when we sleep for a short

time to get refreshed?