Sleeping is not, as is often assumed, an unambiguous phase and is not merely the opposite of ‘being awake’. Someone who sleeps at night goes through a number of separate sleep cycles, which we can easily distinguish from each other and which have various biological functions. This applies to people of all ages, but in babies and small children the number of cycles and the times at which they occur are different. Knowing when and why these cycles occur will help you better understand your child’s sleep patterns. This will help you see if there is a sleep problem or if it is simply a manifestation of these natural cycles.
Types of sleep
Scientists divide the sleep state into five main stages, ranging from dozing through light and dream sleep to increasingly deeper sleep. One of the most important differences useful for parents to know is the difference between the light phase of sleep , known as rapid eye movement (REM ) sleep, and deeper non-rapid eye movement (non-REM) sleep .
REM sleep : Rapid eye movement sleep is the state in which we dream. It is the first stage of sleep to develop in a baby after six months of pregnancy and is vital for brain development. During REM sleep, the body shuts down, the brain receives extra blood and warms up, indicating a higher level of activity. This is likely the time when a baby’s brain processes what he experienced during his waking hours.
REM sleep is very important for the development of babies and that is why it takes a lot of time. At birth this is 50 percent of their dormant state, which is reduced to about 33 percent by the age of three. In older children and adults, REM sleep accounts for 25 percent of the night’s sleep.
From the age of two, most children are aware of their dreams, which can be very vivid, and start to talk about them. You can almost see it in your mind! Most children jerk occasionally during sleep, have rapid eye movements, and breathe irregularly when they dream.
As the night progresses, REM sleep increases, occurring mainly in the early hours of the new day. Because REM sleep strengthens the mind, someone who wakes up too early often feels a bit foggy-headed for the rest of the day. This applies to both adults and children.
Non-REM sleep : During this slow stage of sleep, your child lies quietly and with relaxed muscles. He breathes regularly and deeply and does not move. This is a state most people refer to as sleeping, but non-REM does not fully develop until the baby is 4 months old. Non-REM means to the body what REM means to the brain. During non-REM sleep, blood is delivered to the muscles, tissue grows or repairs, and hormones are released for growth and development.
The significance of sleep cycles for the child
In a newborn, full-term baby, the sleep cycle lasts about 50 to 60 minutes, but increases to about 90 minutes at about 3 months, a pattern that is then maintained throughout life. Regardless of the length of the cycle, your child is most likely to wake up during the lighter sleep periods between cycles. Your child may sit down, move or mumble at times like this, but if left alone he will usually fall back asleep on his own.
A newborn baby enters the REM state as soon as he falls asleep, while an older baby or child enters non-REM sleep first. It takes a baby 15 minutes to fully fall asleep, although this happens faster for most children. Once they are asleep, it takes about 10 minutes to reach deep sleep and during this stage of sleep it is almost impossible to wake your child . This is very important when using a sleep training method . When baby takes longer than 20 minutes to fall asleep, it may indicate a problem, such as late naps or incorrect sleep associations .
If you put your child to bed around 7:30-8:00 PM, the first sleep cycle will last until about 9:00-9:30 PM, and the second until about 10:30-11:00 PM. At this time, most parents go to bed and often think that their child will wake up because of the noise they make. However, it is more likely that the child will wake up anyway, and while it is of course better to take it easy, there is no need to be too careful.
Unfortunately, adult sleep cycles do not coincide with children’s, so your child will often wake up when you are in a deep sleep. This happens especially after 2 a.m., when the child’s REM sleep increases. There is little you can do about this, except leave the visits to your child – if necessary, partly to your partner.
Sleep stages in the older baby
From the age of 3 months, when babies are put to bed, they enter a deep sleep phase, which repeats in the morning. They sleep lightly (REM sleep) for most of the night.
- Deep sleep: early in the night
- Light sleep and dreaming: most of the night
- Deep sleep: towards morning