What Is Sleep?
REM sleep and non-REM sleep

Sleep is divided into two states: Rapid Eye Movement, or REM sleep and non-REM sleep.

If you can easily go to sleep and you get enough sleep simply isn't an issue. However, when you cant sleep and you're suffering from sleep deprivation then sleep becomes a major issue. It can be helpful to understand the basics of what makes sleep sleep.

So let's look at the two states separately first:

Non-REM Sleep
This type of sleep has 4 stages of sleep going from drowsiness or light sleep to very deep sleep.

Stage I sleep is when a person begins to fall asleep and is drowsy. Their thoughts drift and they are ebbing away from being aware of being awake. When someone moves from being in Stage I into Stage II they may have a "sleep start" which is when they suddenly jerk and move back into being awake. This occurs in children and adults and is perfectly normal.

Stage II is a slightly deeper sleep than Stage I but it's still light. The changes in the body are not visible and can only be seen by monitoring the brain waves - large slow waves with short bursts of rapid activity. A person in Stage II sleep is easily woken and the person might not have known that they were asleep! Stage II sleep accounts for about half of the total sleep time.

Stage III is a deeper sleep and it becomes harder to wake the sleeper.

Stage IV is deeper still. In stage IV the heart rate, blood pressure and body temperature falls and breathing slows.

In Stage III and IV the body is relaxed and still - it is recovering. However, sleepwalking and hand banging can occur in non-REM sleep and it is the time when toddlers may have a night terror.

REM Sleep
This is when breathing and the heart rate become irregular and there is more blood flowing to the brain. Dreaming will occur - if your child is woken up whilst dreaming she will remember her dream. REM sleep is thought to be the time when your child processes his day and files it in his memory.

Little smiles, twitches or movements under the eyelids are often seen and your child may stretch out.

REM sleep occurs about every 60 minutes in children and the length of REM periods increase during the night, so the first one may be only 5 minutes but the final period could last up to an hour. It is a light sleep and the sleeper can be easily woken during this time.

Young children spend more of their sleep in REM sleep than adults - babies spend half of their sleep in this type of sleep, three year olds spend a third and adults only a quarter. As children develop and spend more time in non-REM sleep they are able to sleep for longer periods without waking as they sleep more deeply for longer.

Sleeping Through The Night
When your child falls asleep she enters into non-REM sleep and quickly moves through the different stages of sleep to reach deep sleep (Stage IV). After Stage IV she will wake up a little and may move or turn over. Then your child will be sleepy and be drowsy again and fall into REM sleep for a short period.

She will then have another period of non-REM sleep. About an hour later she will be aroused again and enter into REM sleep, but this time, for longer. For the rest of the night she will then be in REM sleep or Stage II of non-REM sleep - both light sleeps. Just before waking up she may have a period of deep sleep.

Young children have more light sleep than older children or adults. During light sleep and at the end of their non-REM sleep they can easily wake up.

If the associations that your child has with sleep are not present e.g. a parent, a pacifier or dummy, being fed, etc. then when your child wakes up she will be unlikely to settle herself and will call out to wake you. If she is able to settle by herself when she wakes up she will be able to go back to sleep quickly and without disturbing you so that you all get more sleep.

Learning to go back to sleep by herself is key to a good night's sleep for everyone.

HOW your child learns can vary and the different methods will be explained in the Sleep Training section so that you can choose which way is right for you and your child.