>> We spend one-third of life sleeping.

The following videos will discuss why sleep
is important, what we know about the biology

of sleep, and what are some
of the common sleep disorders.

We hope that you will have a better
understanding of the benefits of sleep

and how to make sure you are getting
the right amount of quality sleep

to maximize your health and happiness.

You might have wondered, as many
people do, why we need to sleep.

Why is it so important?

You will spend nearly a third of your
life sleeping, that's a lot of time.

Think about it, when you sleep, you're
unaware of your external surroundings.

You lose all perception of the outside world.

In fact, as soon as you fall asleep,
most of your senses are turned off.

You're unaware of the sights, and the
sounds, and the smells around you.

This is an extremely dangerous state
to be in, especially if you're prey

to a larger animal on a food chain.

This is why most animals find a safe
place to sleep, why we, as human,

sleep in room in safe environment.

Why would you naturally turn
off all of your senses

if sleep weren't critically
important for maintaining health.

This gives you reason to learn
about sleep and all of its benefits.

Sleep increases your concentration levels.

This allows you to learn and focus in
school, it boosts your immune system

so that you can avoid getting sick, and
thirdly, it increases your emotional wellbeing.

During sleep, human growth hormone
is released from your brain.

It helps your body grow, repair
damage, and build muscle.

The most important function of sleep on the
brain is its role in learning and memory.

Memory formation is broken
down into three processes.

The first is encoding.

This happens when you're awake
and take in new information.

The second is consolidation.

This happens when you sleep, and the
new information is stored in your brain.

The third is retrieval, which is when the
stored information in your brain is accessed

and recalled or, in other words,
when you remember the information.

The deepest stage of non-REM
sleep, known as slow wave sleep,

is when memory consolidation happens.

How does this work?

Sleep promotes the formation of new
connections between brain cells.

These connections are called synapses.

Synapses are where your memories are stored.

It's been found that more synapses are formed
when well-rested versus a sleep deprived state.

Therefore, when studying for exams, you
should keep in mind that an extra hour

of late-night studying might
be doing more harm than good.

You might be surprised that
while sleep is a natural process,

more than half of all adults claim
that they do not get enough sleep.

This is why it's so important that you
learn about the mechanisms of sleep.

The amount of sleep you need actually changes
throughout your life; depending on your age

and how much energy you expend in a day.

Infants need about 16 hours of sleep a day,

while teenagers need about
nine hours on average.

Adults tend to only need about
seven to eight hours a night.

The amount of sleep you need also increases

if you've been deprived of
sleep in the previous days.

On average, you should get one hour of
sleep for every two hours you spend awake.

This is a 1:2 ratio.

So, say your day is 16 hours long.

You wake up at 7 A.M. and you
go to bed at 11 P.M. This means

that you should get 16 divided
by 2, which is 8 hours of sleep.

This is a good way to keep track of how
much sleep you need on a day to day basis.