- Nobody actually sleeps in one go. We wake up several times a night, even if we do not remember these arousals.
- A baby sleeping through the night should actually refer to his ability to sleep unassisted throughout the night.
- Some infants older than 6 months old have sleep troubles mainly because they did not learn how to self-soothe to go back to dreamland.
- Babies’ sleep cycles are shorter and show different patterns from ours.
- Your baby moves and squeaks in his sleep. Before rushing to him, it is better to wait a brief moment. You might just wake him up unintentionally.
- Once your baby figures out how to fall asleep unassisted, he will effortlessly start stringing sleep cycles together.
- Take all the necessary safety precautions if you opt for bed-sharing.
- Do not focus only on the quality and quantity of night sleep – the benefits of day-breaks for children (and their parents) cannot be underestimated.
In your opinion, what percentage of children wake up every night? The answer is simple: 100%! It’s true, all babies wake up during the night. In a Canadian study, parents reported that their babies woke up on average three times a night, while actigraphy showed eight awakenings per night.
The term “sleeping through the night” is overused and emotionally distressful for parents. In fact, it is the very first milestone all parents of infants long for. At some point in early parenthood, we feel pressured and experience some kind of parental competition. It seems assimilated into good parenting skills. Those whose baby sleeps through the night feel proud to have passed the parenting test. Those whose little one doesn’t sleep peacefully during nighttime wonder how to crack the “all-night-long-sleeping-baby” code. Sleep leaves some parents scratch their heads when questions like “Does my baby have a problem?” or “Should we change our approach?” come to their minds.
What does “sleeping through the night” actually mean?
If somebody asks parents if their baby sleeps through the night, they should, technically speaking, always reply negatively. We all wake throughout the night, sometimes partially and sometimes fully. Nobody sleeps straight through the night and neither does your baby. So, I would like to reassure those parents in doubt. It is totally normal that newborns wake up every 2 to 3 hours a night. In fact, it is to be expected that 100% of newborns will wake up in the night, dropping to 20-30% of six-month olds.
So, “sleeping through the night” does not mean your baby enjoys a night of 10 to 12 uninterrupted hours of sleep. Instead, it specifically refers to his ability to sleep unassisted throughout the night. Therefore, parents’ true goal should be getting Baby to transition between sleep cycles without crying for help to fall back asleep.
What do we know about sleep?
Before the 1950s, scientists believed that when we sleep, our brains and bodies stopped functioning. We were entering a fully passive state, allowing us to recover from the previous day. In 1953, researchers discovered that sleep was much more complex than it appeared to be. In reality, we are anything but in an inert state when sleeping: our brain goes through different phases of activity. Surprisingly, at certain times of the night, the electrical activity of our brain is almost as intense as when we are awake.
Sleep is one of the earliest and most instinctive human behaviors. It is believed that micro-awakenings between cycles have been part of our internal alert system for centuries. Our ancestors, who lived in caves or small camps, had to protect themselves at all times from dangerous predators. Since humans are not capable of sleeping with only one eye open, the best solution for tribe members was to remain alert during regular intervals at night. Each person became more alert to their surroundings and to potential danger. They fell asleep at different times and were never in a deep sleep simultaneously. This made it possible to always have at least one person being vigilant. Thus, the different phases of sleep probably originate in the human survival instinct. And, because of these micro-alarm clocks, nobody actually sleeps in one go.
Also, genetics do influence sleep time duration. That explains why some babies come into the world more predisposed to sleep smoothly. Parents cannot influence the biological aspects of their child’s sleep. However, they can help their baby to set up for better sleep thanks to positive learning techniques.
Even if many pieces of research about sleep have been conducted since these first findings, it remains a very ill-known topic. There is still an air of mystery surrounding sleep. Researchers are constantly experimenting to understand what is going on in our brain and body before, during, and after sleep. This subject matter has yet to be explored much more deeply.
How does sleep work?
Prior to exploring the practical insights, it is important you understand the way sleep works. This will allow you not to worry unnecessarily, to understand the normal development of your child’s sleep, and to put in place the appropriate techniques to put him to sleep in the best conditions. Sleep is not just the opposite of “being awake”. It involves a complex series of stages through which all humans progress. This will not only help you understand night awakenings but also respond adequately and know how adults’ sleep cycles are structured differently than the newborns’.
Sleep is built on two successive sleep cycles throughout the night and during naps: the Rapid Eye Movement (REM) and the Non-Rapid Eye Movement (NREM) sleep. When we fall asleep, we enter the NREM sleep. Our whole body relaxes and calms down. Our breathing is calm, and we present a resting face. During NREM sleep, the baby does not move, his face and muscles are relaxed, his breathing is almost inaudible. Only a few occasional sudden movements can disturb this feeling of serenity. During this phase, the nervous system recovers, which is why NREM sleep is also called the “quiet sleep”.
The REM phase on the other hand, which is also called the “active sleep” or “paradoxical sleep”, occurs at the end of each sleep cycle (except for newborns). It is associated with dreams and promotes the memorization of learning.
Image from « Your Body Does Incredible Things When You Aren’t Awake »
In fact, one sleep cycle is divided into 4 stages.
- NREM stage 1: The “drowsy sleep” stage represents the beginning of the sleep cycle and is considered as a transition period between wakefulness and sleep. It can be compared to the state of meditation or daydreaming. Since we are in a relatively light stage of sleep, we wake up quickly and easily.
- NREM stage 2: During this first “true sleep” stage, we enter in a light and more stable sleep. We become less aware of our surroundings, our breathing and heart rate become more regular and the body temperature drops. During this stage, we wake up due to intrusive noise or light.
- NREM stage 3: This is the so-called “deep sleep” stage where the muscles relax, blood pressure, and breathing rate drop. During this third NREM stage, we sleep profoundly and can hardly be woken up. You could transfer your child from the car to the crib or speak loudly over the phone nearby and only notice minor signs of arousal. In the event that a baby seems cranky or cries as soon as he wakes up, it is possible that he may have opened his eyes right after the deep sleep stage. It can take parents up to ten minutes to calm him down. Of all of the sleep stages, stage 3 is the most restorative. The body and muscles restore from the stresses of the day, the immune system strengthens itself and the human growth hormone is released.
- REM: Active sleep directs the course of brain maturation in early life through the control of neural activity. More blood flows into the brain and the brain temperature raises. REM sleep is easily detectable in babies. You may catch your child mimicking the suction as if he was drinking milk, making faces, smiling, squeaking, and testing his speech, breathing irregularly, kicking, and moving. You also notice his or her eyes moving under the eyelids. This is also when children consolidate information and memories from the day before and when dreaming occurs since their brain is more active. We also know that bambini as young as 2 years old dream during the REM phase as they tell their parents about their dreams. Unfortunately, language development does not allow younger children to certify that they are dreaming or to describe the purpose of their dreams. Research has shown that, after about seven months growing in the womb, the first rapid eye movements are seen for fetuses. Since clear REM sleep characteristics have been observed for newborns, it is reasonable to think that they are also little dreamers, although difficult to prove. Their dreams are probably a replayed sequence of daily experiences. They become more complex with time when the brain and the language develop. Nightmares also occur during the REM stage but only appear around toddler time (peaking between ages two and three).
It is important to realize that sleep does not progress through the four stages in a linear sequence (see below illustration). Sleep begins in stage 1 and progresses into stages 2 and 3. After the deep sleep stage, stage 2 is repeated before entering REM sleep. Once stage 4 has come to an end, we usually return to stage 2.
Same same but different?
Your newborn may have your eyes or your nose, but when it comes to sleep, the two of you are not alike. Babies’ sleep cycles are unique compared to adult sleep cycles.
Newborns only experience two of the four stages: stage 3 and stage 4. They spend about 50% of their sleep in the REM stage (going up to 80% for premature babies and third-trimester fetuses), compared to only 20% to 25% for adults. As a result, babies spend about 8 hours in REM sleep versus an average of 2 hours for grown-ups. A newborn’s sleep cycles are short, consisting of a restless sleep phase followed by a slow sleep phase.
Furthermore, whereas adults start with light sleep, newborns enter sleep through an initial active REM stage. After 3 months, a baby’s REM and NREM sleep reverse; he will enter in NREM sleep first for the rest of his life.
Active sleep helps protect them from surrounding overstimulation, process all mentally-recorded information and observations made during the day. Babies are exploring a totally unknown world where absolutely everything is a new discovery and arouses their curiosity. The accumulated information needs to be organized in different compartments of their brain. They have to sort out the memories that seem important and the details that can be forgotten. This causes them to sleep more than adults.
For about half of the time, newborns are in an active sleep which allows for frequent arousals or awakenings. This is necessary for regular periods of feeding. The frequency of times where a newborn wakes up depends mainly on their feeding needs. Young children spend probably so much time in REM sleep because peaceful sleep allows brain development. Around 4 months old, babies start cycling through all 4 stages of sleep, instead of just two. The first 3 or 4 hours of the night are mainly spent in a deep sleep and cannot easily be awakened.
Example of a sleep cycle for a baby aged 2 to 6/9 months
Each cycle lasts on average from 50 to 60 minutes for the first nine months of life. A newborn will go through about 14 to 19 sleep cycles daily. These shorter cycles explain the higher frequency of waking up and their significant sensitivity to environmental stimuli compared to adults. Anything can make a baby’s eyes open when he is in a light sleep: hunger, noise, discomfort, temperature, or even just the brightness of the room. The length of the cycles gradually increases over the years, and it is only at around 3 or 4 years of age that children’s sleep cycles become comparable to the adults’ version. Less time is spent in REM sleep while simultaneously the sleep cycle itself lengthens.
A complete adult sleep cycle, from falling asleep to REM sleep, lasts between 90 and 110 minutes (this varies from one person to another and from one night to another). Our brain goes through 4 to 6 cycles per night. The first sleep cycles have relatively short REM stages and long periods of deep sleep.
The NREM-stage 3 may involve risks for co-sleeping parents. For those who have opted for bed-sharing, the risk of accidentally crushing or suffocating their baby is highest at this stage.
It is also during deep sleep that sleepwalking, night terrors, or stammering can occur. The control of the muscles shifts within this restless sleep phase, meanwhile, a part of your brain remains blocked in deep sleep. Later in the night, REM periods lengthen and deep sleep time decreases. Since the last third of the night may include mostly REM sleep, it is common to wake in the morning out of the last period of REM and recall your dream.
What should new parents expect?
Newborns need a lot more hours of sleep than adults. Their hours of sleep range between 14 to 17 hours per day, more than any other age group. In comparison, most healthy adults need between 7 to 9 hours of sleep per night to function at their best. If you live in the Netherlands, France, or Belgium, you will probably manage to get slightly more than eight hours per night, whereas the average American sleeps 6.8 hours a night.
Newborns sleep most of their time, but this does not happen in one go. They sleep no more than 2 or 3 hours at the time, meaning that a period of 24 hours is divided into about 8 sleeping and waking periods. These frequent interruptions make new parents’ life quite unpleasant. The adult’s circadian sleep-wake cycle is regulated by light and dark. Sleeping at night and being awake during the day are behaviors related to our biological internal clock. However, these rhythms take time to develop, resulting in erratic and specific sleep patterns in newborns. From birth until the age of 4 to 6 weeks, a baby makes absolutely no distinction between day and night.
In addition, their biological clock (or circadian rhythm) is not yet set to 24 hours. The sleep of humans stalls rather around 25 hours. According to the Harvard Gazette: “External clocks don’t exactly match the biological tickings inside ourselves. Many measurements led to the conclusion that the internal clock period is actually closer to 25 hours. The biological clock was thought to drift toward a 25-hour day unless it is set back an hour each day by exposure to morning light and to external clocks. This situation is blamed for a long list of sleep problems.”
Nothing will wake up a sleeping baby faster than the sound of his mother’s head touching a pillow! Babies, especially newborns, do not follow a rhythm that is established from the beginning onwards. Since babies and adults do not have synchronized sleep cycles, the parents’ sleep is constantly interrupted by bursts of crying episodes, limiting the amount of time spent in a deep sleep. The irregularity in a newborn’s schedule and short rest periods are often at the root of the new parents’ exhaustion. When coming straight out of the deep sleep stage, they feel very tired or even disoriented when their baby cries in the middle out the night. To overcome fatigue, they can recharge the batteries thanks to well-deserved 20-minute siestas. Remember to schedule specific wake up times. This way, your brain will wake up at an appropriate stage in its sleep cycle and you will wake up refreshed. If you decide to set your alarm clock for a one-hour nap, you will most likely emerge from a deep sleep and wake up more tired than you were before you laid down.
“If you get tired learn to rest, not to quit.” – Banksy
The sleep cycle mechanism and length are thus identical and equally important during naps than during nighttime. The diurnal sleeping breaks boost the brain, improves mood, and stimulates memory function. So, do not focus only on the quality and quantity of night sleep – the benefits of day-breaks for children (and their parents) cannot be underestimated.
What should parents do during partial arousal?
During the night, adults cycle back and forth between REM and non-REM sleep and experience brief occasional waking. Adults, except insomniacs, some postmenopausal women, and others who may be struggling with mental illnesses, manage to bridge the gap between two sleep cycles without difficulty almost every single night. A “micro-alarm clock” turns off and we wake up briefly to change positions in bed, pull the duvet, or to change the way our pillows sit. Very often the next day, we don’t even remember these brief moments.
Children also go through brief moments of awakening. Partial awakenings may last only a few seconds and up to several minutes. These micro-awakenings, also known as partial arousals, allow the baby to change position, which is beneficial for the skin, and muscles. During this in-between-cycles moment, babies also check their surroundings and may cry out of hunger or incapacity to fall back asleep. Any external element can be a source of discomfort (light, humidity, or temperature), and can disturb newborns as they go through this delicate period. Any invasive stimuli can prevent them from entering a new cycle. Your presence or gestures could get him out of his sleep and prevent him from getting into the next sleep cycle. That is why it is recommended to wait a few seconds before rushing to your child to give him the opportunity to fall back asleep on his own (if his basic needs have been met).
At the beginning of a baby’s life, he may feel lost when waking up briefly. Even if they are ephemeral episodes, he may feel helpless in the face of the situation, especially if he has become accustomed to falling asleep while rocking, stroking or with a bottle in his mouth. So, he does the only thing he knows how to do: cry out for Mommy and Daddy’s help. Just like talking and walking, falling asleep alone is a skill you learn, and connecting two sleep cycles is a real learning experience for most children. Some were born with this ability, others must go through the trials and failures to control the ability to fall asleep alone. Babies and older children who have not learned to self-soothe to fall back asleep after brief arousal are inclined to experience sleep troubles later in their life. That is the reason why I consider we should teach children to adopt positive sleep habits from an early age.
This overview hopefully gives you a good idea about what happens during the stages of a sleep cycle. This will help you to understand your baby’s sleep-wake behaviors and patterns to act and plan the day-night activities accordingly. Always trust your parental instinct. If you hear that your child is not only going through a transitional phase but is crying to send you a clear message (such as hunger or discomfort), do not hesitate to check on him. Ignoring that your baby is screaming, crying, and turning 50 shades of purple to avoid the habit of being spoiled and cuddled to sleep can be harmful. Since it is strongly advised not to let a baby cry unattended for long periods of time, take him in your arms if he needs to be consoled. The faster you meet his needs, the sooner your baby calms down.
If you are a lucky parent whose baby enjoys long stretches of sleep, I would not jump for joy too early. Early childhood is a long road full of obstacles. Sleep patterns evolve for the better or the worse based on the infant’s developmental stage. If you would like to get more information on how to improve the quality and the quantity of your child’s sleep, schedule your first free consultation now! It is a free and non-binding offer.