Baby sleep cycles: what you need to know

Understanding your baby’s sleep and wake cycles can help during what can be a trying (and tiring) time. Check out our guide on infant sleep cycles.

Sleep is vital for a baby’s growth and development but parents are often unsure of how long or how often their baby should sleep. 

Unfortunately, there is no one size fits all answer to infant sleep cycles, all babies are different. Your baby might opt for long naps during the day and wake often during the night, but your sister’s child opts for quick slumber sessions in the daytime without waking at all through the night. Meanwhile, your friend’s baby’s sleep cycle may include elements of all the above.  

On top of that, babies are also likely to change their sleep patterns throughout their first year, so just as you think you’re ‘on top’ of your baby’s sleep cycle, it’s possible they’ll switch it up and keep you guessing.

Before you get frustrated, remember that babies are biologically programmed to sleep more lightly and have more awakenings than adults and that it won’t last forever. 

“Parents are often concerned that their baby can’t settle themselves to sleep or that they’re waking frequently at night and then catnap during the day - that is, they just have one sleep cycle during the day,” says Professor Harriet Hiscock, associate director of research at the Centre for Community Child Health. “But there’s a broad range of ‘normal’ [infant sleep cycles]. Some babies, just due to their temperament, will settle easily and get into a nice pattern of sleeping three or four hours a time at night.”

How much sleep do they need?

Babies under the age of one sleep a lot, unfortunately just not for extended periods of time! Babies under three months typically sleep on and off for a few hours at a time for a total of 11 to 19 hours a day. They need to wake in the night to feed and, in fact, it’s desirable for them to do so, not just to top up a tiny belly but to experience some closeness and physical contact.

The type of sleep your baby gets will change as they grow. In the early months it is likely to be 50 percent active, involving shallow breathing as well as twitching arms and legs, and 50 percent quiet, which is about stillness and deep, regular breathing. By contrast, adolescents and adults tend to remain fairly still and quiet when they sleep.
Baby sleeping on his belly
After around three months, infant sleep cycles tend to switch between light (also called REM) and deep sleep (NREM). Light sleep is when you dream and can up wake up easily. Deep sleep is a lot more restful and is when children or adults tend to struggle to wake up, feeling drowsy when they do. With premature babies, around 80 percent of their shut-eye time is spent in light sleep, with deep sleep difficult for their tiny bodies to achieve. This REM sleep very early in life is thought to assist in brain development.

What's with the late night party baby?

 Waking at night is partly due to children’s worry about being separated from their parents, and overcoming this is necessary for becoming independent at night. By six months, baby sleep cycles should feature less waking at night. 

“All little babies need to feed at night and certainly up until the age of six months,” Professor Hiscock says. “After six months, most babies can get their nutritional needs met during the day. If they’re still waking at night and that’s a problem for parents, that’s when you can do something about it.”

Although every baby is different, by the age of eight months the majority are able to settle themselves back to sleep, depending on whether they’re still being fed at night and how successful settling strategies have been.  And from the magic one-year mark, babies are usually sleeping longer – from eight to 12 hours a night – and waking less often, and may only want one or two daytime naps. 

“Sometimes there are medical reasons why babies don’t sleep well, and one of the things parents often worry about is food allergies, particularly cow’s milk allergies,” Professor Hiscock says. “If in addition to settling problems the baby’s got crying that’s persisting beyond the colic 12-week period, has eczema, they’re vomiting or have blood or mucus in their poo, or if there’s a close family member with a food allergy, that’s when we start to investigate whether an underlying food allergy could be causing the sleep problem.” 

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