A Useful Guide to Your Baby’s Sleep Cycles

When it comes to your baby’s sleep, you probably have a lot of questions. But one thing you know for sure is that babies sleep a lot...but rarely at the times most convenient for you. You’ll do anything to crack that baby sleep code, am I right? One thing that can lead the way in this effort is understanding your baby’s sleep cycles.

Here we’ll cover what baby sleep cycles are, how they change during infancy, and how you can utilize this knowledge to your advantage to help your baby sleep. We also partnered with Chloe Fries, a pediatric sleep coach from La Lune Consulting, to find out how to use your knowledge of sleep cycles to help your little one sleep her best.

What are baby sleep cycles?

According to sleepcycle.com, “Sleep cycles are part of our internal biological “clocks,” or the regularly occurring patterns of brain waves which occur while we sleep.”

Baby sleep cycles are also the regularly occurring patterns of brain waves happening while they’re asleep - but that cycle doesn’t look quite the same as an adult’s. Whereas an adult sleep cycle from start to finish lasts about 90 minutes, a baby’s is about 45 - 60 minutes long. What’s happening within the cycle also looks very different when your little one arrives in this world.

A baby’s sleep cycle will undergo a lot of change in the first year, so let’s start by looking at a newborn’s sleep cycle.

Newborn Sleep Cycle

A newborn’s sleep cycle is unique. Until around the 4-month mark (when sleep starts to get more “adult-like”) your baby really only has 2 sleep cycles:

Newborn Sleep Cycle 1: Light (Active) Sleep
Newborn Sleep Cycle 2: Deep (Quiet) Sleep

The time spent between the two cycles is about equal:spending about 50% of the time in light or active sleep and the other half in deep or quiet sleep. This is quite different from adult sleep in that we are only in a light sleep state (or REM sleep) for about 20% of the time, according to Healthline.

So what does this mean for your newborn?

Because so much of their time is spent in light sleep, it’s easy for a newborn to wake up. If you’ve ever said the words, “She’s such a light sleeper,” about your newborn, it’s not a coincidence. A newborn with frequent wake-ups both during daytime and nighttime sleep can be exhausting and trying for you, but it’s also normal!

There are lots of reasons a baby wakes frequently (including a need to eat with that tiny tummy of theirs), but a lot of it has to do with so much time spent in light sleep as well not yet having learned the skill of putting themselves back to sleep independently.

But this 50/50 split won’t last forever, and as your baby gets a bit older you’ll see those sleep cycles start to mature.

Teaching Your Baby to Connect Sleep Cycles

Once you have an understanding that your baby isn’t ever capable of sleeping in one giant snooze cycle each night, you’ll be better prepared to teach them how to put themselves back to sleep between each of those sleep cycles.

The fact is, when you move through sleep cycles at night, you wake up, too. Ever so slight, you don’t even notice (or remember). That’s the goal you want to work toward with your baby.

Connecting Sleep Cycles at Night

Getting your baby to move from one sleep cycle to the next without waking up can be a big feat for parents - especially once they’re old enough to realize that you’re no longer around.

Many sleep experts suggest that 4-6 months is a great time to sleep train your baby in order to coincide with their new sleep patterns. Sleep training is the best way to help your baby move from one sleep cycle to the next without fully waking.

In our article, A Helpful Guide to Sleep Training Your Baby, we give in depth insight into how to go about this process. This includes:

eliminating sleep props,
establishing a sleep routine,
and finding a method that works best for you and your baby.

We also suggest using different sleep aids, such as a Dreamland Baby weighted sack, that ensure your baby stays calm and relaxed through each sleep cycle

Pediatric Sleep Coach Chloe Fries discusses how important it is for your baby to become an independent sleeper. She shares:

"When little ones are helped to sleep, they will wake after one or two sleep cycles and look for help back to sleep in whatever way they were helped in the first place. They literally don't know how to fall asleep any other way! Choose a sleep coaching method you feel comfortable with and guide your baby to independent sleep so that they learn how to fall asleep all by themselves and fall back into a deep stage of sleep after they've reached a light stage, thus connecting their sleep cycles on their own all night and nap long."

Avoiding the 45-Minute Intruder Between Naps

Stirring between each sleep cycle is common. But it's the wake-ups that you want to avoid. The goal is for your baby to string together at least 2 sleep cycles to get a solid 1.5-hour nap. Otherwise that 45-minute intruder might wake your baby and you'll end up with a cranky little one on your hands!

If you have a great napper who’s learned how to be an independent sleeper and can put themselves to sleep on their own, then your baby will be able to move back and forth without a hitch. Unfortunately, not all babies seamlessly move from deep to light sleep.

Using the same suggested tips from above will help for both nighttime sleep and naps. Learn more strategies in our article, "How to Stop the 45-Minute Intruder."

How Your Baby's Sleep Cycles Change Around 4-6 Months

In our article, “Getting Through the 4-Month Sleep Regression,” we discuss how your baby’s sleep begins to change. Though this period can have you pulling your hair out, questioning why your baby is sleeping poorly all of a sudden, it’s actually not a regression at all. Instead, your baby’s sleep is maturing and becoming more adult-like.

Whereas a newborn really only has two main stages of sleep, around the age of 4 months, your baby’s sleep cycle evolves to having about 5 different stages.

Though your baby’s sleep cycles are changing, the length of each cycle will take time to move toward that longer 90-minute mark. But as your baby grows, they will have longer periods of deep sleep, making it easier for them to sleep longer and longer stretches of sleep at night as time goes on.

Movement from 2 stages of sleep to 5 doesn’t happen overnight. This is something that will continue to change through infancy and young childhood.

These are the 5 stages of sleep your baby will experience in a 50-60 minute timeframe.

Stage 1 Falling Asleep - the first 10 minutes: Eye movement begins to slow down and your baby begins to fall asleep.

Stage 2 Light Sleep - minutes 10 - 20 : The second stage of sleep is still light. Brain waves begin to slow down, but your baby is still easily startled at this time.

Stage 3/4 Deep Sleep - minutes 20 - 30: Then your baby moves into restorative deep sleep.

Stage 5 REM (Rapid Eye Movement) Sleep - minutes 30 - 45: This is the active sleep state where brain growth such as learning and memory occurs. You may see eye flutters and movement.

Arousal - minutes 45 - 50: Your baby is back into light sleep as they finish their sleep cycle. They will either go back to sleep or wake up if they haven’t yet learned skills to put themselves back to sleep.

Sleep looks a lot different than the newborn phase, so you can understand why this will be an adjustment for your little one. Combine this with the fact that your baby is beginning to have more awareness of her surroundings, and it can be tough for your baby to go back to sleep between sleep cycles.

Chloe Fries shares what this means for next steps with your baby:

"Many parents around this time start noticing that naps get shorter and many even start seeing more nightwakings than they did when their baby was a newborn. If you're experiencing this it means that your baby is getting to the end of one sleep cycle and they don't know how to get into another one. So, they cry out looking for whatever helped them to sleep in the first place. However that doesn't mean that you now have to deal with multiple nightwakings, difficulty getting your little one to sleep, or short naps for years. It simply means that your baby is ready to learn how to fall asleep and connect those new sleep cycles all on their own!"

Having an understanding of how your little one’s sleep works can actually help you get their sleeping back on track.

Why It’s Helpful to Understand Your Baby’s Sleep Cycles

So we’ve covered what a newborn’s sleep cycle looks like as well as an older baby’s, and you might be thinking to yourself, “So what?” I mean, science is cool and all, but does knowing this help you as a parent?

Yes!

Next we’re going to cover some ways you can use your knowledge of baby sleep cycles to start helping your baby (and you) sleep better and more soundly.

Knowing When to Put Your Baby Down

Though we often say to put your baby down, drowsy but awake, this can actually work against you if you don’t do it carefully.

Since your baby enters a light sleep state first, you need to make sure you avoid putting your baby down during this stage of sleep. Because if you put your baby down during light sleep, it’s highly likely they will wake up as soon as you lay them down. We know you’ve been there...you breathe a (very quiet) sigh of relief seeing that your little one is finally asleep and you gently place them in their crib. You tip-toe away and before you’ve even made it to the door, they cry out.

In light sleep, even the slightest disturbance can wake your little one. This is why we’re all about creating the perfect calm and quiet sleep environment with a weighted sleep sack and white noise...the more relaxed your baby is, the less likely they’ll wake up.

Here are your options for putting your baby down:

Fully awake. There is nothing wrong with putting your baby down fully awake if they are good about putting themselves to sleep. However, many babies will protest with this method...especially if they’re not adequate relaxed.
Drowsy. Putting your baby down when they’re showing obvious signs of sleepiness can be great. But you have to be careful...there is a fine line between drowsy and already entering light sleep, so don’t wait too long to lay them down.
In deep sleep. The last option is to hold your baby in your arms until they’ve reached a deep sleep and THEN lay them down. Though we don’t typically recommend this for an older baby who you are trying to sleep train, it’s normal for young babies to fall asleep snuggled up to you.

Where parents can get this wrong is if they put their baby down too soon...it happens ALL the time! You think, “Hey, my baby has been asleep for ten minutes and my arms are about to fall off - time to put them down!” And then, they wake up. NOOO!!

Though you’d think 10 minutes would be enough time for your little to be fully asleep, it’s actually not.

So, how long does it take for a baby to go into a deep sleep?

In looking at our chart above, you’ll see that it will take about 20 minutes for your older baby to reach a state of deep sleep.

Dr. Sears writes, “In the early months, infants enter sleep through an initial period of light sleep. After twenty minutes or more they gradually enter deep sleep, from which they are not so easily aroused.”

We know it will be tempting to put them down sooner, but wait at least 20 minutes, and then you should be good to go!

How do you know when your baby is in deep sleep?

Not only do you want to watch the clock on this one, but you’ll also want to look at your baby as they sleep for signs of deep sleep.

The easiest way to determine when your baby is in a deep sleep is if they aren’t making noises and are completely still. If you see any flinches or hear your baby grunt or whimper, they aren’t yet into a deep sleep.

Full Sleep Cycles are Important for Quality Sleep

Ensuring that your baby has a peaceful environment where they can complete each sleep cycle (while learning to connect them) without interruption is important.) Chloe Fries leaves us with her expertise on why good sleep is so important for your little one:

"Getting proper sleep plays a big role in your baby's temperament, mood, the maturation of their brain, the building of their immune system, and their ability to learn and understand new skills. Furthermore, the growth hormone is only secreted when your baby is sleeping. In other words, sleep is fundamental when it comes to your baby's overall growth and development. Not to mention, the impact lack of sleep has on your well-being, ability to successfully complete tasks throughout the day, mood, and health. When your baby isn't sleeping, neither are you, and both your AND your baby's health and well-being are equally as important when it comes to getting the sleep you both need to be your best selves."

If you are struggling to help your baby connect sleep cycles and are in need of a sleep solution, we encourage you to 1) Try a Dreamland Baby weighted sack and 2) reach out to Chloe Fries at La Lune Consulting. Because it's all about those zzzs.