Sleep is something we share in common with most other living creatures in the world. Every single person spends a third of their lives sleeping. This time of reduced reaction to external stimuli and altered state of mind is necessary to the body. During sleeping hours, the human body goes through a significant number of tasks. It resets and restores immune, nervous, skeletal, and muscular systems. The memory indexes and archives new information. Without sleep, the body crashes and shuts down.
Heads up: This article was commissioned as a part of the Adam Rush Project. It was an experiment I did a few years ago to see if having books written by ghostwriters would be commercially viable. It wasn't. That said, the following article was written by someone else and not yet edited to my standards. I hope to find time to rewrite it myself in the future, but for now, read with caution.
Disclaimer: I wish I could tell you that I’m a doctor, but I can’t. I’m just an inquisitive author with a background in science and a love for practical research. The content of this article is provided for informational purposes only and should not be construed as medical advice. If you want medical advice, ask a real doctor.
The sleep cycle changes over the course of our lives. As we grow older, it evolves from one state to another. The amount of sleep we need changes according to our age, habits, and physical and mental activity. Disrupting the cycle can cause disorders such as insomnia, narcolepsy, parasomnias, and others. It can cause significant detriment to health in general. Good sleeping habits are essential, especially at early ages. The brain uses sleep to regulate cognitive and language development in children.
One of the primary mechanisms that regulate sleep is the circadian rhythm. This function uses an inner clock located in the suprachiasmatic nucleus, or SCN. The SCN is the part of the brain that regulates the synchrony among all the systems in the body. It follows a 24-hour cycle. It also regulates temperature, hormones, metabolism, and other essential functions of the body. The circadian rhythm uses the senses to keep the body in synchrony with the environment. One of the most valuable tools for the SCN is the light input it acquires from the optic chiasm. That’s why we suffer jet-lag when we travel from one time zone to another. The circadian clock has to reboot itself over and over until it gains synchrony again.
Infants
In the case of newborns, the circadian cycle is not well developed. The sleep cycle is not yet synced to external stimuli like sunlight, sound, or temperature. Instead, the inner clock responds to closer and more basic needs, like the need for food. A newborn’s belly is small. They need a significant amount of nourishment during their early development. The consequence of this is that the child will wake up and signal for attention every two to five hours. After that time, they eat and then go back to sleep shortly after that. The infant sleep cycle also responds to uncomfortable situations. When the baby has a dirty diaper, or they spent too much time in the same position, they wake. As the brain develops, the newborn learns the meaning of particular external stimulus. The concept of silence is one of the first external indicators. Silence means nobody is around, which means no food, protection, attention, or interactions. Another example is when babies feel drowsy after they eat. The child’s metabolism sends a signal to the brain to go to sleep to process the recently received food.
The infant’s interactions with the environment tune the circadian rhythm. The newborn will sleep from 11 to 18 hours every day, with no recognizable pattern in the beginning. After the first year, the infant gains a regular sleeping cycle.
Newborns often cry during their sleep, signaling for attention they don’t need. They could also wake up for a few seconds, cry and get back to sleep by themselves. These are also consequences of the circadian cycle process.
Parents should avoid unnecessary stimulation when feeding infants or changing diapers at night. It includes talking, playing, chanting or even turning the lights on. Keeping minimal interaction is a good way to reinforce the idea that night time is a time for sleeping.
As time advances, the child learns how to interact with the environment. In the beginning, infants wake whenever the stomach feels empty. But bit by bit the newborn begins to understand the cycle. At around 4 to 6 months old, the inner clock recognizes and internalizes the meaning of nighttime. The child does not need to eat in the middle of the night anymore. At between 6 and 9 months old, most children can sleep through the night. They sleep less as they get older. At around nine months, the baby will sleep an average of 10 to 12 hours during the nighttime. They complement their sleep with several naps during the day, each lasting from one to two hours.
It’s important to understand that the habit of falling asleep is a learned ability. When an infant shows signs of drowsiness, it’s a good idea to put them to bed immediately. Don’t wait for them to fall asleep first before laying them down. This way the drowsy child will learn to fall asleep by themselves.
During this period the infant will also discover the relation between sound and sleep. The child will learn that the quiet hours of the night are more suitable for sleeping than the daytime. Factors like the development of motor skills, senses, and metabolism may disrupt sleep. Separation anxiety is another factor that could disrupt sleep in an infant. The feeling of abandonment can cause stress and keep the child from falling asleep.
Children thrive under routines. They sleep better when they do the same things before going to bed. Taking a bath, singing a particular lullaby, or reading can help establish bedtime. In time, infants understand that those particular tasks signal that it is time to sleep. Once you establish a bedtime routine, doing the tasks with your child will help them to fall asleep.
Toddlers
After about a year, the child will enter the toddler stage. At this juncture, the toddler will sleep between 11 and 14 hours a day. Most of the sleep will take place at night. The toddler will take one or two naps during the day, lasting from 1 to 3 hours each. This period is also an excellent opportunity for conditioning. Encouraging the toddler to take the naps at the same time every day will make sleeping easier. It will also help the kid sleep better during the nighttime. It’s all about the force of routine.
The toddler stage is the beginning of the age of exploring. The child is experimenting with language and communication. They learn what an idea is and how to convey the idea to other people. They also understand the sense of togetherness. They understand they are part of a family and society. The toddler will also gain more liberty due to the development of motor skills and ability to walk. All these events allow them to interact with the world and stimulates the imagination. During sleep, the brain processes new information and generates vivid and imaginative dreams. A byproduct of this is having nightmares. The toddler is entering the age of monsters in the closet or under the bed.
It is the age when active dreams come to the toddler’s sleep time. Before that, the reduced amount of stimulus often produces more abstract dreams. Toddlers have more vivid dreams and are often not prepared to understand how they work. For them, there’s no difference between the dream and the real world. Their imagination merges both mind states. As Goya said once, “the sleep of reason creates monsters.” That quote applies in particular for a one or two-year-old toddler.
A good practice is, if the child likes to, to talk about the nightmare. Rationalizing the dream helps the toddler to distinguish between fantasy and reality. Finding the logical cracks will show them the nature of dreams and how they are not real. Support and the feeling of safety are the best allies in this stage.
Preschoolers
When the kid reaches their third year, the preschooler stage begins. Children of this age might start to replace most of the daily naps with one 11 to 13 hour sleep time at night. As in the toddler stage, dreams and nightmares are a recurring issue. An increasing imagination and more stimulus from the outside world fuel their dreams. It is also the stage when the child begins to interact with people beyond the family circle. It’s the time when the child will meet the consequences of those social interactions. The child will witness other people’s reactions to various emotions. The child processes all this new information during sleep. There’s something new and exciting every day. And new data is available for the brain to learn and evolve.
School Age
School obligations alter the sleep habits of children. Life transforms during the period between 6 and 13 years of age. During this stage, children sleep from 9 to 11 hours every night. School, homework, friends and video games fill their waking hours. This new life affects the sleeping cycle. At this point, the circadian rhythm is fine-tuned to a 24-hour period. It follows the natural day-night cycles of the Earth. But the child’s new activity-and-emotion-filled schedule can also generate stress, anxiety, and tiredness. It can affect the sleep cycle and cause disorders such as insomnia or night terrors.
Sleep deprivation at this age can cause changes in mood and behavior. A kid can become more irritable or hyperactive. Tiredness can degrade body functions like metabolism or the immune system. It is why sleep is critical for this age. The sleep habits acquired at this age will most likely continue into adulthood. It is important to reinforce good sleep habits at this period in a kid’s life.
Teenage and Beyond
The development of the sleep cycle is the journey of the brain’s formation. Every factor involved is a symptom of a deeper, more complex machinery doing work. By the age of two, a child would have spent more time asleep than awake. And by the age of three, the brain will reach 90% of its adult size. There’s a direct correlation between those two facts. The brain absorbs information during the waking hours and processes it during sleep. Because of that, most of the brain development happens when the children are sleeping. Far from a random sequence of tiresome baby cries, it’s the mask of something beautiful. Looking at that detail from this point of view, having to rise from the bed is not a bad thing at all. It gives us the chance to witness the process that makes us who we are. Next time you have to go and feed your son or daughter at midnight, take a minute to enjoy the rise of the circadian cycle.
Summary
- Your sleep cycle drastically changes as you grow from newborn to adulthood.
- The need for food controls the infant sleep cycle.
- After their first year, children begin to have vivid dreams and nightmares.
- Sleep is critical to the growth and development of the brain in children.
- Developing a consistent sleep habit is most important once children reach school age.