How do babies sleep? As parents, we get asked common questions like, is he a good sleeper, or is he sleeping through the night? But the reality is, light sleep and night wakings, are a healthy part of development and are necessary for our babies’ survival.
While we can’t erase the exhaustion that comes with taking care of our babies, the five facts below, can help us worry a little less, and help us understand the nature of our baby’s sleep. We can take comfort in knowing that our babies’ sleep habits are not a cause for alarm, but are normal, and are actually markers of good health.
Five Fascinating Facts About How Babies Sleep
1. Baby Sleep Patterns Are Different than Adult Sleep Patterns
We adults depend on circadian rhythms to regulate our sleep patterns. That is the timing and duration of sleeping hours known as our sleep/wake cycle, but babies aren’t born with a built-in biological clock already ticking.
The circadian rhythm for babies takes time to develop, which is why newborn sleep schedules are so erratic and unpredictable. It takes newborns anywhere from one to three months, and possibly six months for these rhythms to start functioning properly.
Enjoying plenty of daylight and avoiding strong lights at night will help our babies distinguish between day and night. Later, this will also help regulate the production of melatonin, the sleep inducing hormone naturally released by our bodies.
Adult sleep patterns versus baby sleep patterns
Even after sleep patterns are established, babies will still sleep differently, because they don’t go through the stages of sleep the same way adults do.
Adults transition throughout stages of REM (active sleep, known as rapid-eye-movement) sleep and non-REM (quiet sleep, known as non-rapid-eye-movement) sleep in 90-minute cycles, and usually enter into deeper sleep quickly after first falling asleep. In total, most adults spend 20-25% of the night in REM sleep.
Babies have shorter sleep cycles, and move from light sleep to deep sleep every 50-60 minutes. Babies tend to wake up during the light sleep stage, but some babies manage to get back to sleep alone, while others require comforting to get back to sleep.
Shorter sleep cycles give babies more opportunities to wake during sleep. They can also take up to 20 minutes to reach deep sleep, which explains why they can be disturbed so quickly in those first few minutes.
Babies’ sleep cycles don’t catch up to the adult standard until they reach their toddler years.
2. Babies Are Light Sleepers
You probably already know babies are light sleepers, but have you asked yourself why? One reason is because of the shorter sleep cycle. Infants, particularly newborns, may actually wake up between full cycles. It’s not so much light sleeping as it is actually learning how to sleep properly.
Another reason is that babies spend about the same amount of time in both non-REM (quiet) and REM (active) sleep, compared to adults who spend only about 20% of their sleep in REM sleep. Refer to my article, “Sleep Patterns for Adults – What’s Normal?”
This means that not only is the infant sleep cycle shorter, but it also includes a lower percentage of deep sleep. It can take up to 20 minutes of light sleep before babies go into a deep sleep, and then REM sleep occurs shortly after. This is part of why babies need to sleep so often.
In the first few months of infancy, light sleep allows hunger to wake babies up to be fed. One of the hardest aspects of parenting a newborn is being awakened every few hours during the night. While night waking may feel impossible to get through when parents are awakened at 2 AM, for babies, their survival depends on it.
Besides needing to feed every three to four hours, babies may wake because they are in pain, need a diaper change, are too hot or cold, or have trouble breathing, for example. Having a shorter cycle of lighter sleep is actually a survival skill for babies.
3. Every Baby Is Different When It Comes To Daytime Naps
A good nap is generally considered to be at least about an hour and a half in length. There are also commonly prescribed amounts of naps per day, depending on age range: three to four naps from three to five months old, two to three naps from six to nine months old, and up to two naps thereafter and into the toddler ages.
Newborns don’t nap as much as they have short windows of waking moments in between sleeping periods of two to four hours at a time throughout the entire day. Our babies’ actual sleep habits may be close to this, or completely different depending on factors like temperament, environment, and daily routine.
For treating daytime napping as a priority, see my article, “How To Help My Baby To Sleep – Six Scientifically-Based Strategies“.
If our babies’ naps are unusually short, but they nap more often or sleep through the night with relative ease, waking only to feed, that’s fine. If our babies nap for more than an hour and a half but take fewer naps overall, that’s fine, too.
What’s most important is the total number of hours spent sleeping in a day of about 14 to 17 hours, depending on the baby’s age. As long as our babies are happy and healthy, deviating from standard daytime sleep habits isn’t such a big deal.
As we’ve seen in this article, babies need a lot of sleep and spend up to 75% of their time sleeping. This is good news because sleep influences learning and memory.
Babies test the limits of their environment continuously when they’re awake. They learn to recognize their parent’s voices, for example. They learn non-verbal cues to express when they’re hungry, or when they’re in pain.
What babies learn is then consolidated and renewed by periods of sleep in between their waking moments. This is what’s referred to as memory reactivation, which requires previous learning while awake.
5. Babies’ Sleep Is Also Strongly Related To Development And Growth
Newborns spend 14-17 hours per day sleeping and this only decreases by two to three hours over the first year of their lives.
If babies spend so much time sleeping, then why do parents always seem so tired? This is because most of that sleep happens in short spurts in the beginning, so parents spend a great deal of time taking care of their babies, and trying to help them fall back asleep.
We saw earlier how infants spend 50% of their total sleep time in the lighter REM stages. REM cycles are when learning and brain development in babies and adults takes place, as discussed in my article, “Heal While You Sleep – Adults“, while input from waking hours is consolidated into memories.
Over the first 3 months of life, the infant’s brain grows by 1% each day, which may explain why they spend so much time in the REM stage.
Those sleepless nights we experience can feel like they last forever, but the truth is, they’ll be gone before we know it. Ask any parent with grown children, and they’ll tell us that the best thing we can do is enjoy this season before it’s gone. Hold our babies a little closer, rock them a little longer, and give them thousands of tiny kisses.
What I’ve learned from writing this post: The main thing I enjoyed learning, as I researched my content for this article, is how beautifully ‘designed’ our bodies are as infants as we start our life’s journey.
I have a better understanding why infants are light sleepers, how through the sleep-and-eat process they learn to communicate their needs, how they learn to sleep due to their sleep/wake cycles, why they need LOTS of sleep to process their learning into their memories, and how their body development and growth is directly related to their sleep.
How precious our babies are!
Just as quality sleep for adults is vital, quality sleep for infants is as vital, if not more so!
Moms, I hope you feel encouraged, and know that we are serving a wonderful purpose in caring for our babies. I hope you’ve learned about why our babies’ sleep patterns seem so sporadic and broken up, making us feel exhausted. Remember this too shall pass. Let’s take care of ourselves too, and visit here again to learn more about sleep.
Please leave your comments and questions below, and be sure to share your own tips that will help others as they read this article.
Happy Deep Sleep,