A study shows that late bedtimes lead to brain changes that limit the ability to cope with negative emotions.
As neuroscientists, we are passionate about issues related to reducing socioeconomic disparities that can influence children’s development. Our goal is to better understand how such disparities affect sleep quality and brain development in young children.
For our most recent work, we recruited 94 children aged 5 to 9 years living in New York, from families of various socioeconomic statuses. Among the participating households, about 30% had incomes below the poverty line in the United States.
The results we obtained indicate that lack of sleep and late bedtimes are associated with functional changes in the brain. These potentially harmful changes are located in regions important for coping with stress and controlling negative emotions.
Our work also reveals that children from families with limited economic resources are particularly at risk of experiencing these brain changes.
Impact on the Amygdala
To measure the impact of sleep deprivation and bedtime schedules on children’s brains, we asked their parents to describe the place where their child sleeps, as well as various family routines and their regularity. We also asked them to note their child’s bedtime and wake-up time.
We then conducted MRI scans on the children to determine the size of a specific brain region called the amygdala, as well as the strength of its connections with other brain regions. The amygdala plays a crucial role in processing emotions and the amount of negative emotions a person feels. It is known that early exposure to adversity can affect the functioning of this brain structure.
We found that children from families with fewer economic resources slept less at night and went to bed later than children from families with more resources. This shorter sleep and later bedtimes were associated with a reduction in the size of the amygdala and weaker connections between the amygdala and other brain regions involved in emotion processing.
This link between socioeconomic disadvantage, sleep duration and schedules, and amygdala size and connectivity was observed in children as young as 5 years old. Our findings suggest that sleep duration and timing are important for the functioning of brain regions involved in emotion processing.
Maintaining Family Routines
During childhood, the brain develops rapidly. Experiences during this period can have long-term effects on brain function, lasting throughout life. Lack of sleep increases the risk of developing mental health problems and interferes with academic success. Additionally, reduced sleep duration can make it more difficult to manage stress and emotions.
As we have seen, children from families or neighborhoods with few socioeconomic resources may be more at risk of stress-related mental health problems, partly due to the negative effects of their environment on sleep quality. But why?
The data we collected suggests that parents who struggle to make ends meet have more difficulty maintaining family routines, which could negatively impact the regularity of bedtime routines, resulting in less restorative sleep for children.
However, it is likely that multiple factors explain the links between lower socioeconomic status and poor sleep quality. Financial difficulties can, for example, prevent the acquisition of comfortable bedding, force children to sleep in overcrowded, too warm, or too bright rooms, or require living in a noisy neighborhood, etc.
Mental Health
The results we obtained argue for the implementation of policies ensuring that all families have sufficient economic resources to meet their children’s needs.
Other studies have shown that providing additional income to families in need can improve not only children’s brain functions but also their mental health and academic performance.
Finally, it should be noted that, until now, most sleep research has focused on adolescents, who are particularly at risk of poor sleep. However, our work suggests that the effects of our environment on our sleep habits are felt much earlier, starting in childhood. Therefore, interventions aimed at improving sleep quality should be implemented as early as possible to be most effective.
