The links between sleep and health – and sleep and body weight, in particular – have become harder to ignore in recent years.
The research has shown a strong connection between sleep deprivation and higher body weight, both in adults and in kids.
And perhaps the most striking connection is that the one may predict the other as a person ages: In fact, a new study in The Journal of Pediatrics finds that the later the bedtime in early childhood, the greater the risk for obesity in adolescence.
The reverse is true, too. Though there’s likely a number of variables involved, the connection may underline the degree to which sleep really does affect how the brain develops, and that a sleep-deprived brain in early childhood may not quite be wired optimally.
But as the new study also shows, the connection may also be partly about the psychological elements associated with an early bedtime.
In the study, from The Ohio State University, the researchers followed nearly 1,000 preschoolers, whose average age was 4.5 at the start of the study. They divided them into three groups depending on when they generally went to sleep at night: before and up to 8:00 p.m., between 8:00 and 9:00 p.m., and after 9:00 p.m. Half of the kids went to be at the middle time, and the other half was divided pretty evenly between the earlier and later bedtimes. The team followed the kids and their families into adolescence and tracked the teen’s body weight.
It turned out that 10% of the tots who had the earliest bedtimes were obese as teenagers. About 16% of the kids with the middle bedtimes were obese as teens, and 23% of the kids with the latest bedtimes were obese as teens. So there’s somewhat of a dose dependent relationship going on here.
But the researchers also looked at another variable, which is linked to bedtimes, and a host of other factors – the emotional tenor in the household. To try to capture this, the team observed the play times of the parents with their kids, and rated what’s known as maternal sensitivity, which takes into account how supportive a mother is, how much she respects her child’s autonomy, and any hostility she shows. Then they ran the data to determine any correlations between this variable, bedtimes and obesity. They found that regardless of maternal sensitivity, earlier bedtimes still correlated with obesity in a child’s teen years – but it was strongest when a child going to bed later also had a less sensitive mother.
“For parents, this reinforces the importance of establishing a bedtime routine,” said study author Sarah Anderson. “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.”