Babies and their sleep cycles…don’t expect your baby to sleep like you!

By Jo Ryan, BA MPH
Understanding the sleep cycles of infants will go a long way to helping you cope with the first few months with your new baby. It’s important to realise their sleeping patterns are quite different from ours.

When a baby is tiny, they need a lot more sleep than we do, and they tend to sleep the same amount during the day and at night. As they grow older, this changes. Babies stay awake for longer periods and their day sleep becomes quite different to their night sleep.

The table below gives a general recommendation for how much sleep a baby needs:

 AgeUp TimeDown TimeAverage Sleeps
 0 to 6 weeks Approx 1 hourRanging from 2-3 hours5 to 6 sleeps in 24 hours
6 to 3 months1 – 1,5 hours2.5 to 3 hours4 to 5 sleeps in 24 hours
3 to 4.5 months 1.5 to 2 hours2 to 2.5 hours3 day sleeps
4.5 to 6 months2 to 2.5 hours2 to 2.5 hours2 to 3 day sleeps
6 to 12 months2.5 to 3 hours1.5 to 2 hours2 day sleeps and 10 – 12 hours per night

 As we know, all babies are different, so not every baby will need the same amount, but this chart gives a good indication of what you should work towards. A newborn baby’s stomach is tiny, which means very young babies will wake often to feed. As babies grow, they are able to ‘stretch out’ the time between feeds, particularly at night. Then they start to sleep for longer periods overnight, and their day sleeps become shorter.

Babies and adults have different sleep cycles

When we compare the sleep cycles of adults and babies, we see they are quite different. Let’s start by taking a look at your own sleep cycles*. When we fall asleep we travel through several sleep stages, with sequences of deep sleep and REM (rapid eye movement) sleep. The latter stage is essential for the healthy life of any adult and is known widely for its association with dreaming. What’s more, during this stage the skeletal system is temporarily paralysed, while brain activity resembles that of the waking brain – the eyes move quickly beneath the eyelids and breathing often becomes irregular. From beginning to end, an adult’s sleep cycle lasts about 90-100 minutes. At the end of a sleep cycle, we either wake up or begin a new cycle, with the periods of REM becoming longer as sleep progresses.

A newborn’s sleep cycle is much simpler than an adult’s, with only two stages – active and non-active sleep. A baby’s sleep cycle is also much shorter than an adult’s, with an average duration of 45-60 minutes for the first nine months, (often even shorter than that).

A usual infant sleep cycle looks like this:
• When a baby first falls asleep they go into ‘active’ sleep, which is very like REM sleep for adults. During this stage, babies are also more likely to wake up. A newborn will spend about 50% of their sleeping cycles in this stage, as opposed to an adult, who spends only 20%.

• About halfway through a sleep cycle, the baby falls into ‘non-active’ sleep, which is characterised by slower, rhythmic breathing, less movement and no eyelid fluttering. Non-active sleep is the end of the sleep cycle, which means that the baby will either wake up or return to active sleep.

From around five to six months onwards, babies develop more stages in their sleep that resemble how adults sleep and they gradually replace non-active sleep. The duration of their sleep cycles also lengthens and the time spent in active sleep shortens.

Babies are not born with the sleep-wake cycles an adult body works with. They are much lighter sleepers than adults, because they spend so much time in ‘active’ sleep. This is why it can take anywhere from six months to one year of age for a baby to sleep through the night, although we all know that some babies can achieve this milestone earlier. From about six months, babies can sleep for longer stretches, but it can take a while for them to build to a solid, uninterrupted 8-12 hour sleep with no wakes whatsoever.

Despite the challenges around sleep with young babies, sleep remains crucial in the early months and years for brain development. Sleep is when babies form the vital connections between the brain hemispheres which influence language, relationships and reasoning. So, even if you feel your baby is getting by without too much sleep, you’ll find once your baby is sleeping the length of time they need for their age, their development will take off and they will be generally more relaxed and cheerful.

Source: The four stages of sleep*

Jo Ryan, BA MPH, is the author of BabyBliss, the bestselling guide on how to calm, settle and establish sleeping routines for young babies. Jo was a paediatric nurse and nanny for 20 years, and now runs a “baby whisperer” support and advice service for parents with young children.