There’s lots of information around about baby sleep cycles and it’s easy for parents to become confused.  However, just like the adults in their lives, babies’ sleep cycles vary depending on a range of individual factors.  Their age, development, feeding, and environment all play a big part in the amount of sleep a baby needs. And when babies are sick or growing quickly, they often want more sleep.  Read on to learn what’s typical when it comes to baby sleep and sleep cycles. 

Why is sleep so important?

Sleep is important for babies to grow and develop. When they’re sleeping, babies release growth hormones and consolidate memories. They are also able to recuperate so they can progress through developmental changes and enjoy being with other people.  Tired babies tend to be grumpy and irritable so their tolerance for play is limited and they don’t feed  well. This can often start a cycle of ‘snacking and napping’ which can impact on the whole family.

What are tired signs?

It can be hard to interpret a baby’s tired cues (signs) as being different from other cues or signals they may give. Every baby has their own unique way of signalling that they’re tired and need to sleep. Some give very clear tired cues; others are more subtle in communicating that they’re tired and need to go sleep.   

Most babies show these tired signs:

• Rubbing their eyes and yawning.
• Stopping what they’re doing and staring off into space with a blank expression on their face. 
• Many babies want to be cuddled and don’t want to play even their favourite games. 
• Snuggling into a parent’s shoulder, lying down on the floor or pointing to their cot.
• Some babies rub their ears and for some strange reason, their eyebrows may appear red.
• Becoming grizzly, irritable and just not happy. 

There is a window of time between when a baby shows tired signs and being easiest to settle.  Missing tired signs can lead to overtiredness and a surge of energy, making it harder for babies to settle to sleep. 

Sleep cycles

Very young babies have sleep cycles that last around 45 minutes.  In the first few months, each sleep period is made up of cycles of active and quiet sleep.  The baby may move around and make noises during active sleep and sleep more deeply when they’re in quiet sleep phases. 

From around the age of 3 months, babies have sleep cycles which are broken into phases of light sleep, deep sleep and REM (Rapid Eye Movement) or dreaming sleep. 

Between 3-6 months of age, many babies reduce their day sleeps to around three each day. They might also be having periods of longer, continuous sleep at night. They continue to have phases of sleep which are divided into quiet, deep and REM sleep.

From around 6 months, babies tend to have their longest sleeps at night.  They can take up to 40 minutes to settle at night and wake more frequently in the early hours of the morning. This is the age and stage when many parents choose to make some changes around how they settle their baby for sleeps. 

Typical sleep behaviour

Babies cycle through stages of sleep – from when they start to drop off to sleep until they wake around 45 minutes later. Within this timeframe, it takes:

• Around 10 minutes for a baby to start falling asleep.
• Within 10- 20 minutes to get into a deeper phase of sleep.  
• Around 20-30 minutes to get into their deepest phase of sleep.
• Up to 30-40 minutes (or less) coming out of their heaviest sleep.  
• Typically, at around 45-50 minutes, a baby will transition into a light sleep phase – this is when they will easily wake.

10 sleep cycle truths

1. Parents cannot control when their baby goes to sleep, or how long they sleep for.
2. It can be easier to settle a baby for sleep at the outset. Resettling after waking can be challenging.
3. Babies tend to settle more easily and sleep longer in their morning sleeps.
4. Until at least six months of age, babies still wake at least twice each night and need feeding.
5. Many babies prefer to sleep in darker and cooler rooms.
6. It’s always important to follow the safe sleeping recommendations for all sleeps, both day and night.
7. As babies get older, they need less sleep and more of their sleep happens at night.
8. When babies are having a ‘growth spurt’, they tend to sleep more for a few days. This is often followed by a surge in their hunger as they need more energy to fuel their growth, grunt and be noisy. It can be useful for parents to wait and see if their baby will resettle before going to them straight away.
9.  Many babies wake on the dot of 45 minutes after they fall asleep. If they’re waking tired and grumpy, it can be useful to try some resettling strategies.
10. Sometimes the first sign of illness is when a baby wants to sleep more. Even before showing any outward symptoms, their immune system wants to be supported by extra sleep.  

For more help with your baby’s sleep cycles

Speak with your Child Health Nurse for more information about your baby’s sleep. Remember, every baby is an individual and has their own unique sleep and settling needs.  

Written for Sudocrem by Jane Barry, Midwife and Child Health Nurse, March 2023.