26% of sleepless children become overweight
Canadian researchers have found that a quarter of children who sleep fewer than 10 hours a night become overweight by age 6. Poor sleep is rampant within the 0-6 years age group: between the ages of 6 months and 6 years old, close to 90% of children have at least one sleep-related problem. Among the most common issues are night terrors, teeth-grinding and bed-wetting.
For the majority, it's simply a stage that passes. But at least 30% of children in this age group have difficulties sleeping six consecutive hours – either because they can’t fall into slumber or they can’t stay asleep. While the effects of lack of sleep on learning are well documented, researchers at the Université de Montréal have found sleepless children can become overweight and hyperactive.
Jacques Montplaisir, a professor in the Department of Psychiatry and director of Sleep Disorders Center at Sacré-Coeur Hospital says that 26% of children who sleep fewer than 10 hours a night between the ages of 2½ and 6 years are overweight. The figure drops to 15% of those who make the 10 hours and falls to 10% among those who sleep 11 hours.
The research team analyzed a sample of 1,138 children and found:
- 26% of kids who didn’t sleep enough were overweight
- 18.5% carried extra weight
- 7.4% were obese
The relationship between sleep and weight could be explained by a change in the secretion of hormones that’s brought on by lack of sleep. “When we sleep less, our stomach secretes more of the hormone that stimulates appetite,” Montplaisir explains. “And we also produce less of the hormone whose function is to reduce the intake of food.” Naps don’t compensate for nightly lack of sleep, Montplaisir adds.
And according to the same study, inadequate sleep could also lead to hyperactivity – 22% of children who slept fewer than 10 hours at age 2½ suffered hyperactivity at 6 years old, which is twice the rate seen in those who slept 10-11 hours per night.
Is it possible that hyperactive children sleep less or that children who sleep less become hyperactive? According to Montplaisir, the second scenario is correct. “In adults, inadequate sleep translates into sleepiness, but in children it creates excitement,” he says. Children were also given a cognitive performance test in which they had to copy a picture using blocks of two colors. Among the children who lacked sleep, 41% did poorly, whereas only 17-21% of children with 10 or 11 hours of sleep per night performed badly.
Problems experienced in childhood risk continuing into later years if nothing is done.
All that said, it’s back to square one for parents coping with a nightly battle to get their toddlers into bed and persuade them to stay there.
A regular bedtime routine can help and it pays to be tough – sorting out sleep problems as early as you can is one way of protecting your child’s health and promoting their healthy development as they grow.