Sleeping … Sleeping … Do we need sleeping ?

Why do we need sleeping? Why do we need sleeping? How many hours do we need? How many hours do we need? What could happen if we don’t sleep?What could happen if we don’t sleep?

Let’s answer one of the questions:

We need sleep for our body to relieve stress, to grow, and also to balance our bodily chemicals.

What could happen if we don’t sleep?

A real case!

Randy Gardner, a 17-year-old high-school student from San Diego, stayed awake for eleven complete days. Although he felt nauseous at times, had difficulty reading, and suffered temporary memory lapses, he had no long term emotional or physical side-affects of the experiment. Measurements have been taken, however, to prove that there are some chemical changes during sleep deprivation that concludes the fact that our body needs sleep

Why does it happen?

Melatonin is a hormone secreted from the pineal gland in the center of our brain. It is released when our eyes begin to register that the sun is beginning to set and darkness begins to fall. This is what makes you go to sleep and is also used in our body to regulate our sleep-wake cycles. If you wonder why older people tend to sleep less then younger people, it is because the amount of melatonin produced in our body seems to lessen as we age.

The two types of sleepREM (Rapid Eye Movement ) – NREM (Non-

Rapid Eye Movement) In total , there are four stages of sleep :

3 for NREM1 for REM

What is NREM ?

NREM is the first type of sleep you enter into when you first fall asleep. Most of our time asleep is spent here.

It is split into 3 stages, with each stage taking you deeper and deeper into sleep.

NREM Stage 1This is the first stage of NREM, starting

from the moment you first fall asleep. Your brain begins preparing you for the deep sleep ahead. Your muscles relax and your breathing becomes slow and steady.

It’s a very light sleep. If you wake up at this stage, you might not even know that you had just been sleeping.

NREM Stage 2

Stage 2 is the next stage of sleep following on from stage 1. Here you’re in a deeper sleep than in stage 1. You can still be woken up pretty easily at this stage but you will certainly know that you had just been sleeping.

Here your body functions slow down even more and prepares for the next stage of sleep.

NREM Stage 3It is the last stage of sleep. Here your body is in a

deep sleep. Waking someone from this stage would be pretty difficult and if you managed it, they would feel very groggy, tired and disoriented. They certainly wouldn’t thank you for it!

Dreams are more common in this stage than other stages of NREM sleep, although you would probably only remember fragments of your dreams if anything at all.

What is REM ? REM sleep is the second type of sleep, often kicking in only after

a full cycle of NREM sleep. This is the stage where most dreaming occurs. REM is

sometimes called paradoxical sleep because brain scans of people who are in REM show that their brains are very active, despite the fact they’re fast asleep.

However, while your brain is active, only your eyes can move. There are exceptions though. Some people have a condition called REM Disorder where by their body is not paralysed during sleep and they can actually act out their dreams.

From the age of 2 onwards, we spend around 20% – 25% of our sleep in REM where as newborns spent around half of their time asleep in REM.

Why do we have two types of sleep?

It is still a mistery why there are two kinds of sleep as we should all have a NREM sleep .

The purpose of REM sleep is not fully understood. Some scientists think REM sleep may have something to do with the role of acting on our memories and making sense of the day, which could explain why newborns have more REM sleep than others as they explore their new world.

Now that we have learned a lot more about sleeping , let’s see what you can remember …

Copy these questions in your folder and answer them!!!

Who will remember more ???

Good luck!!Good luck!!

1) Why do we need sleeping? 2) What is Melatonin used for in our bodies?3)How many types of sleep are there? How do

you call them?4) Describe “with your own words” each of their

stages . 5) Do scientists know why there are two kinds of

sleep ? Which is healthier?