Sleep and Early Brain Development
Our series on infant sleep and its effects on development, which we co-authored with the journal Infant Behavior and Development, includes this post. A special issue on the effects of newborn sleep on cognitive, social, and physical development as well as strategies for parents and professionals to support good sleep and development in infancy included the highlighted study.
Learning And The Circadian Rhythm Of Sleep And Wakefulness
Newborns sleep for roughly 75% of the day throughout the first few months of life. They sleep almost half of a 24-hour cycle by the time they are nine months old.
In order to create an adult-like pattern of being awake during the day and asleep at night, a circadian rhythm—or inner clock-like signals—develops during the first year. Nonetheless, 20% to 30% of toddlers still have night terrors or restless nights after becoming one year old.
Healthy development in infants depends on getting enough sleep. According to research, learning and brain development in newborns are correlated with the amount and quality of their sleep.
For instance, newborns who sleep for shorter periods of time have worse memories, and those who have trouble falling asleep at night have a harder time remembering new phrases.
Cycles Of Sleep And Stress Reaction
Infants' circadian rhythm develops in tandem with their sleep-wake cycle to adapt to stress. Cortisol, a stress hormone that gives the body a burst of stored energy to assist it get through the stressor, is released when stress is recognized. The additional surge facilitates the fight-or-flight response, which helps the person cope with the stressor.
Not all stressors are severe or strong in character.
For instance, when an infant is overstimulated, hungry, or sleepy, they frequently cry and fidget during diaper changes. Every encounter and alteration in a baby's day has the potential to cause stress and trigger a cortisol response, which primes the body to handle stress.
When cortisol is continuously released and stays high, it becomes unhealthy. Poor learning and functioning have been associated with such high levels, indicating that excessive cortisol may impair brain development.
Adults usually have high morning cortisol levels, which gradually drop throughout the day, and low evening cortisol levels as sleep draws near. Though few research have examined the relationship between newborns' cortisol and sleep cycles, it is believed that infants imitate the adult day-night cortisol circadian rhythm.
Does a baby's sleep and cortisol levels affect their language and learning later on?
In order to better understand if newborns' sleep quality has an impact on their language development and general learning capacities, we conducted a study. The infants came from middle-class, white families and attended a top-notch daycare center in a U.S. state in the Southeast.
Parents were asked about their infants' sleep habits, sleeping environment, and the amount and quality of their sleep when the newborns were eight months old and again at fourteen months.
The infant's learning and cognitive skills (e.g., imitating, looking, or pointing to an object when asked where it is) and communication and language skills (e.g., nodding head to indicate yes, using sounds/words to seek attention) were assessed by the child care provider at both time points.
We also took morning saliva samples from the infants at both times to start investigating the part cortisol levels play in the relationship between sleep and learning in the early years.
Better sleep at night improved an infant's language and cognitive skills as a toddler
We investigated whether infants with regular sleep schedules and adequate sleep at night exhibited superior language and learning/cognitive abilities compared to infants with irregular sleep schedules and inadequate sleep at night.
We discovered that stronger learning and language skills at 14 months were linked to optimal sleep at 8 months, which is defined as getting enough good sleep through the night. According to these results, getting a healthy amount of sleep before turning one year old may have an impact on the language and general learning of the young child.
Better sleep for toddlers is associated with higher levels of the stress hormone cortisol in the morning
We also examined the relationship between sleep and the morning cortisol stress hormone levels of 14-month-olds. We discovered that kids with the best night's sleep also had the highest levels of the stress hormone cortisol in the morning.
Adults typically have greater cortisol levels right after waking up. Therefore, toddlers who slept better at night may have more developed brains, as evidenced by their higher cortisol levels.
Read Also: Do Adopted Kids Always Have Difficulties
Early Brain Growth Is Improved By Sleep
According to our research, getting enough sleep during infancy was linked to improved language and learning abilities in toddlerhood. The notion that sleep promotes early brain development is supported by these findings.
Sleep causes the production of chemicals called neurotransmitters, which reinforce and build the brain's pathways for forming memories of the things a child learnt that day. This is one explanation for why sleep aids in the development of an infant's brain.
Infants who get enough sleep are also better prepared to learn the next day. Learning chances for young infants usually come from encounters during the day. Babies who have had a good night's sleep may awaken feeling calmer and more eager to interact.
On the other hand, babies who don't get enough sleep could wake up feeling lethargic, agitated, and less prepared to interact with others and learn. Caregivers should assist infants and toddlers in obtaining uninterrupted, restful sleep at night since sleep is crucial for retaining previously learned material and setting the stage for future learning.
How can parents encourage the growth of their kids' brains?
By creating routines at home that begin at around the same time every day and let the baby know that bedtime is approaching, caregivers can help babies get a good night's sleep.
To encourage increased infant relaxation, parents may, for instance, give a warm bath, sing a lullaby, read a peaceful story, and massage their infant after the last breastfeeding or bottle feeding of the day.
To help their baby transition from being alert and active to being calm and prepared for a long sleep, parents should attempt to reduce ambient stimulation. For young newborns, a dark, peaceful, screen-free environment is ideal for sleeping.
Parents can employ techniques to help their infants self-regulate and go back to sleep if they wake up throughout the night. Parents shouldn't assume that all newborns will react to a nighttime routine in the same way; instead, they should be aware of each baby's specific sleep needs.
For instance, sleep disturbances are common in newborns with medical illnesses, neurodevelopmental disorders, and trauma. In order to understand how to create healthy sleep habits for their infants, caregivers of these babies might want extra assistance.
In conclusion, parents who are sensitive to the unique demands of early infants while creating their sleep schedules can assist their children in getting a good night's sleep so that they are prepared to learn and acquire new abilities when they are awake.
Early brain development may be more mature as a result of getting enough sleep, as seen by greater morning cortisol levels.