UNIVERSITY PARK, Pa. — Sleep can affect a child’s attitude and behavior, as many parents can attest, but a consistent bedtime may be more influential than sleep quality or duration, according to a new publication authored by researchers in the Penn State College of Health and Human Development and Penn State College of Medicine.

The study, published Nov. 8 in the Journal of Developmental and Behavioral Pediatrics, showed that children who followed a consistent bedtime routine and fell asleep at the same time each night displayed better control of their emotions and behavior when they were under stress or working with others.

Adwoa Dadzie, doctoral student in biobehavioral health, and Orfeu Buxton, the Elizabeth Fenton Susman Professor of Biobehavioral Health and Dadzie’s doctoral adviser, led a team who analyzed sleep and behavior data from 143 six-year-old children in the Penn State Intervention Nurses Start Infants Growing on Healthy Trajectories (INSIGHT) study.

When children in the longitudinal INSIGHT study were newborns, their mothers received training in responsive parenting, which involves responding to a child’s emotional and physical needs in a warm, timely and consistent manner. Penn State researchers previously found that responsive parenting training in infancy and early childhood can help promote healthy sleep and reduce childhood obesity. This new analysis from the study, according to Dadzie, demonstrates continued benefits of regular sleep timing.

“Children who had consistent bedtimes were generally able to regulate their behavior and emotions,” Dadzie said. “On the other hand, children whose bedtimes and sleep times were all over the place showed more impulsivity and less control.”

Understanding how sleep affects child behavior

Children in the study wore a monitor on their wrist for seven days to measure their nighttime sleep and activity. The devices monitored multiple aspects of sleep — time the child fell asleep, time the child woke in the morning, the midpoint of sleep timing, how efficiently the child remained asleep and the total amount of sleep the child got each night.

These data were compared to the child’s performance on a task designed to see how they responded to frustration. Each child selected a toy that they wanted to play with from a large selection. The chosen toy was placed in a clear box and locked. The child was given a set of keys, none of which unlocked the box. The researchers then observed the child for self-regulated behavior — including self-talk and trying each key — and a lack of self-regulation — including throwing the keys without trying them all. After four minutes, the researchers returned with a working key and allowed the child to play with the toy.

The researchers also watched the children decorate a picture frame with their parents. Children’s behavior was identified as prosocial if they engaged in cooperative activities like sharing and cooperation or antisocial if they destroyed craft supplies or talked back to their parents.

Results showed that the more a child’s bedtime varied each night, the worse they regulated their behavior and emotions. For example, a child whose bedtime varied by 20 minutes a night over the week of the study typically displayed more self-regulation than a child whose bedtime varied by two hours across the week.

“It’s amazing,” said Buxton, a Social Science Research Institute co-funded faculty member. “Parenting matters. When parents establish clear structures and respond to their child’s needs appropriately, children have better outcomes in weight regulation and behavior — even years later.”

Responsive parenting: Lower BMI, better control of behavior and emotions

Between 2012 and 2014, researchers in the INSIGHT study recruited families with firstborn infants for a childhood-obesity-prevention intervention. Participants were divided into two groups: a control group that received information about child safety and an intervention group that received information about responsive parenting.

Parents in the responsive parenting group were educated on how to respond to infant behavior states like fussiness; alertness, which includes feeding and interactive play; drowsiness; and sleeping.

Through the first three years of their lives, children in the responsive parenting group had lower body mass indices (BMIs) than children in the control group. The program content did not exclusively focus on weight; parents learned to recognize their child’s hunger and satiety signs, to allow their child to decide when the child was full, and — later in the child’s development — to establish routines and expectations around food, sleep and behavior regulation.

When children in the INSIGHT study were six years old, they returned to the College of Medicine for more evaluation. The current study on bedtime and behavior used data from that visit.

“The results clearly indicated that sleep regularity is important for prosocial and age-appropriate behavior in children” Dadzie said.

The researchers said that some parents — those who work evenings for example — might not be able to participate in a bedtime routine with their children, but those parents can still take steps to parent more responsively.

“Every parent can establish clear standards and routines for their children,” Buxton said. “They can respond appropriately and promptly to children’s needs. We now have eight years of research on the INSIGHT project demonstrating that when parents are responsive to their children, they raise healthier children.”

Lindsay Master, data scientist in biobehavioral health at Penn State; Emily Hohman, associate research professor in the Penn State Center for Childhood Obesity Research;  Ian Paul, principal investigator of the overall study and University Professor of pediatrics and public health sciences at Penn State College of Medicine; Jennifer Savage Williams, professor of nutritional sciences and director of the Penn State Center for Childhood Obesity Research; Erika Hernandez Acton, assistant professor of leadership and organizational behavior at Binghamton University; Sara Tauriello, graduate research assistant in pediatrics at Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo; and Stephanie Anzman-Frasca, associate professor of pediatrics at Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo, also contributed to this research.

The National Institute of Diabetes and Digestive and Kidney Diseases, the National Center for Advancing Translational Sciences and the Children’s Miracle Network at Penn State Children's Hospital supported this research.