Making sure your toddlers are in bed by 8 p.m . lowers their chance of becoming obese teenagers, new research shows. Bedtimes after 9 p.m. doubles the likelihood of obesity later in life, reported a study.
“For parents, this reinforces the importance of establishing a bedtime routine,” said Sarah Anderson, lead author and associate professor of epidemiology, The Ohio State University College of Public Health. “It’s something concrete that families can do to lower their child’s risk and it’s also likely to have positive benefits on behaviour and on social, emotional and cognitive development,” Anderson said.
Obesity has more than doubled since 1980 and become a major health concern. More than 1.9 billion adults, 18 years and older, were overweight. and of these over 600 million were obese, estimates the World Health Organisation. In 2014, 41 million children under the age of 5 were overweight or obese .
Body mass index (BMI) – the weight in kilograms divided by the square of the height in meters (kg/m2) – is used to classify overweight and obesity in adults. Overweight is BMI equal to or more than 25, and obesity equal to or more than 30.
Obesity can set kids up for a lifelong struggle with weight and health complications that can accompany it, including hypertension, diabetes and heart disease.
The new research, which appears in the The Journal of Pediatrics, used data from 977 children who were part of the Study of Early Child Care and Youth Development. That project followed healthy babies born at 10 U.S. sites in 1991.
Anderson and her co-authors divided preschool bedtimes into three categories: 8 p.m. or earlier, between 8 p.m. and 9 p.m., and after 9 p.m. The children were about 4 ½ years old when their mothers reported their typical weekday bedtime. The researchers linked preschoolers’ bedtimes to obesity when the kids were teens, at an average age of 15.
They found a striking difference: Only 1 in 10 of the children with the earliest bedtimes were obese teens, compared to 16% of children with mid-range bedtimes and 23% of those who went to bed latest. Half the kids in the study fell into the middle category. A quarter had early bedtimes and another quarter went to bed late.
Because the emotional climate at home can influence routines such as bedtime, Anderson and her colleagues also examined interactions between mothers and their children during a videotaped playtime. Scientists call the measurement “maternal sensitivity” and it factors in maternal support, respect for the child’s autonomy and lack of hostility.
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Regardless of the quality of the maternal-child relationship, there was a strong link between bedtimes and obesity, the researchers found. But the children who went to bed latest and whose moms had the lowest sensitivity scores faced the highest obesity risk.
The researchers also found that later bedtimes were more common in children who were not white, whose moms had less education and who lived in lower-income households.
Putting a child to bed early doesn’t guarantee he or she will fall immediately into a deep sleep, but establishing a consistent bedtime routine makes it more likely that children will get the amount of sleep they need to be at their best, Anderson said.
The study, however, doesn’t answer questions about how sleep time intertwines with other factors that contribute to weight gain in childhood, including physical activity and nutrition.