Understanding your baby’s sleep cycles and patterns can feel like trying to solve a midnight mystery. One week, they’re snoozing with no problem at all, and the next, they’re wide awake every 45 minutes. What’s going on?
First and foremost, rest assured that this is normal and that you’re not alone! All babies go through stages of deep sleep followed by stages of erratic sleep.
What’s important to remember is that baby sleep is fundamentally different from yours, and those sudden wake-ups are actually a sign of a healthy, growing brain.
So, while you rub your tired eyes and nurse that extra-large cup of coffee, we’ll discuss baby sleep cycles so you know what’s going on, what to expect, and when you can get a little rest of your own.
Key Takeaways
Table of contents
- What is a baby sleep cycle?
- Baby sleep cycle milestones
- Tips to make baby sleep cycle changes easier
What is a baby sleep cycle?
At its most basic, a baby sleep cycle is the loop of time it takes for their body to move through the different stages of rest, from light sleep to deep sleep and back again.
While adults have long sleep cycles that last between 90 and 120 minutes, a baby’s cycle lasts between 30 and 50 minutes. That means your little one reaches the vulnerable “waking zone” at the end of a cycle twice as many times as you do. No wonder they wake up so often!
When an adult moves between sleep cycles, they usually just roll over and go right back to sleep. But for a baby, hitting that light-sleep stage can startle them wide awake.
Understanding these quick loops and how they change as your baby grows is the secret to helping them connect cycles for a deeper, more restful sleep (for them and for you).
Baby sleep cycle milestones
Newborn sleep patterns (0 to 3 months)
Newborn sleep patterns are often completely unpredictable. In the first three months of their life, your little one sleeps about 16 to 18 hours a day, but it happens in very short bursts. That’s because newborns spend 50% of their time in active sleep.
It’s within this active phase that their little brains are working overtime to grow and process the world around them. You might notice their eyelids fluttering, their arms and legs twitching, or them making little grunting noises. That’s their brains being active!
Don’t rush to scoop them up when you see or hear these things happening. They’re not awake. They’re just doing important developmental work.
One major milestone to be on the lookout for is their internal clock starting to normalize so that there is less day/night confusion. To help them figure that out, keep things bright and lively during their daytime wake windows and dark and calm during their nighttime wake windows.
The four-month shift
Around 12 weeks after birth, your little one may start waking up every 45 minutes, even if they were previously sleeping for much longer stretches. This is the infamous four-month sleep regression!
While it will feel like a huge step backward for tired parents, it’s actually a big biological leap forward for babies. Their brain is officially upgrading from a simple two-stage newborn sleep pattern to a more adult-like four-stage cycle. As a result, they spend more time in light sleep.
When they finish a quick 45-minute cycle, they enter a "waking zone" where they look around to make sure everything is how it was when they fell asleep. If it’s not (say they fell asleep in your arms but wake up alone in their crib), they’ll sound the alarm.
Helping them learn to feel comfortable falling asleep in their crib is the secret to surviving this stage.
Infant sleep patterns (4 to 12 months)
Between four months and 12 months, your baby will start finding a more predictable rhythm.
From four to eight months, their total sleep needs drop to around 12 to 15 hours, and their naps settle into a steady routine of three or four a day. They’ll also start learning how to roll over, sit up, and crawl. These new skills can be a major cause of them waking up so often.
Safety Reminder: When your baby starts showing signs of trying to roll over, it’s time to transition out of the swaddle (if you’re using one) and into a sleep sack or jammies so that their arms are free to move.
From eight or nine months to 12 months, their sleep needs may stay the same, but they’ll start to transition to a solid two-nap schedule. They may also develop separation anxiety, causing them to resist bedtime (and protest when you put them down) because they anticipate missing you.
Toddler sleep patterns (12+ months)
After 12 months, your baby, who’s now technically a toddler, will need between 11 and 14 hours of sleep a day, but their nap schedule will change dramatically.
Most toddlers transition from two daily naps down to one long nap (usually in the afternoon) that can last anywhere from 1.5 to 2 hours. This often happens somewhere between 14 and 18 months old.
Making this switch can be tricky, but you’ll know they’re ready when they completely refuse their morning nap, or if they take that morning nap but then are wide awake come bedtime.
When they do switch to one nap per day, expect some cranky time as their body adjusts. You might consider moving bedtime up by 30 minutes or so to prevent them from becoming overtired while they (and you) get used to their new big-kid routine.
After these switches in sleep patterns settle down, things will be more consistent until 24 and 36 months. Both of those ages mark additional sleep regressions.
At 24 months, a lot of big changes are happening, including potty training and teething (just to name a few). These major life stages can interrupt the sleep patterns your little one has built for the last six months.
At 36 months, more big changes are on the horizon. They’re developing their motor skills; growing their vocabulary, memory, and imagination; and continuing to get a handle on not wearing a diaper anymore. Just as with the 24-month regression, these can interrupt their sleep.
For tips on how to cope with these changes, check out these articles from the Newton blog:
-
The 2-Year Sleep Regression: Causes And How To Survive It
-
3-Year-Old Sleep Regression: Signs, Causes, and How to Cope
Tips to make baby sleep cycle changes easier
Navigating these baby sleep cycle changes doesn’t mean you have to resign yourself to sleepless nights!
First, try putting your little one down drowsy but awake so they learn to fall asleep without you holding them or nearby.
Next, optimize their sleeping environment so that it’s cool, dark, and quiet. Consider installing blackout curtains over the windows and running a white noise machine to mask any sounds that might wake them up.
(Important safety note: Make sure curtains, cords, and the white noise machine are kept well away from your baby’s sleep space, and keep white noise at or below 50 dB near the baby, with the machine placed at least 7 feet away.)
Finally, practice the one-minute rule. When your baby whimpers or whines between sleep cycles, pause and wait 60 seconds before going to them. They might just be in an active sleep phase and will drift back to sleep all on their own.
Rest easy, baby!
At the end of the day, navigating baby sleep cycles is all about consistency, patience, and the right environment.
Switching to an ultra-breathable Newton Crib Mattress is a total game-changer for you and your baby! Its unique design allows air to flow freely, helping your little one regulate their temperature between those tricky sleep cycles.
Pair it with a breathable, organic sheet and a cozy sleep sack, and you’ve got the perfect recipe for safer, longer sleep for your baby and much sweeter dreams for the rest of the family.
Frequently asked questions
Does my baby’s body temperature actually change during a sleep cycle?
Yes, during a sleep cycle, their body temperature goes down, hitting its lowest point around 3:00 a.m.. This is why a nursery that feels comfortable at bedtime might cause your baby to wake up cold in the middle of the night.
What is “periodic breathing,” and why does it happen during light sleep?
Don’t panic if your newborn pauses their breathing for five to 10 seconds, then pants rapidly. This is called periodic breathing.
It’s completely normal during active REM sleep because the part of their brain responsible for breathing is still maturing. It typically disappears completely by six months of age.
How does what I feed my baby affect their sleep cycle?
Evening breastmilk naturally contains high levels of melatonin (the sleep hormone) and tryptophan (an amino acid that triggers serotonin production), which helps soothe babies to sleep.
Formula doesn’t change like breastmilk does, but it does contain larger protein molecules that take longer to digest. Because of this, formula-fed babies may sleep longer before getting hungry and waking up.
