Children who don’t get enough sleep may be more likely to become overweight or obese than kids who typically get enough rest, a Danish study suggests.
The researchers focused on 368 normal weight children between 2 and 6 years old who were at risk for becoming overweight because they were born at a high birth weight, had heavy parents or came from a low-income family.
At the start of the study, parents recorded sleep diaries for their children over 7 days, noting how much total rest kids got and whether the children took naps, slept through the night, had difficulty falling asleep or waking up, or suffered from other sleep issues. Parents also completed food diaries.
The children who got the least amount of night time sleep on average were more likely to become overweight during the following 1.3 years, the study found. Kids who became overweight were also more likely to consume a lot of sugary foods and drinks.
“Our study showed that children with the highest sleep variability consumed higher amounts of added sugars and sugary beverages but lower amounts of fruits and vegetables compared with children with lower sleep variability,” said lead study author Anna Rangan of the University of Sydney.
“This suggests that children who have less variable sleep duration, or better sleep routines, have better dietary quality than those who may have less stringent sleep routines,” Rangan said by email.
While plenty of previous research has linked inadequate sleep to obesity in both children and adults, less is known about toddlers and young children with a high risk of obesity because of their own birth weight or parents’ weight and income, researchers note in the International Journal of Obesity.
At age 2, kids should get 11 to 14 hours of sleep in a 24-hour period, including naps, according to guidelines from the American Academy of Paediatrics. From age 3 to 5, kids need 10 to 13 hours of sleep including naps and starting at age 6 doctors recommend 9 to 12 hours of sleep.
At the start of the study, the children were getting an average of 10.7 hours of sleep a night, though this ranged from 8.8 hours to 12.5 hours.
Children who slept more than 10.7 hours on average had significantly less weight gain than kids who slept less than 10.4 hours, the study found.
Kids who slept less were more likely to have trouble falling asleep - and to go to their parents’ bed at night - than children who got more rest, the study also found.
One limitation of the study is that researchers relied on parents to accurately recall and report on children’s sleep routines, the authors note. It’s also possible that some unmeasured or poorly measured factors like socioeconomic status, family characteristics or physical activity might influence the connection between sleep and obesity.
Even so, the findings add to previous research linking inadequate sleep to increased caloric consumption and poor food choices, said James Gangwisch, a psychiatry researcher at Columbia University in New York who wasn’t involved in the study.
“Eating a poor diet, inadequate physical activity and being overweight can also contribute toward disturbed sleep,” Gangwisch said by email.
Parents can help children get more sleep by enforcing a regular sleep schedule even on weekends and holidays, creating a calming bedtime routine, and removing electronics from the bedroom, said Stacey Simon, a paediatric sleep psychologist at Children’s Hospital Colorado and the University of Colorado Anschutz Medical Campus in Aurora.
“Teaching kids that sleep is a priority – and modelling this behaviour – by blocking out enough time to get the right amount of sleep is important, especially as children get older and become more independent,” Simon, who wasn’t involved in the study, said by email.
“In addition to weight, we know that insufficient sleep has a negative impact on children’s behaviour, mood, and cognition,” Simon added. “So getting the right amount of sleep is extremely important.”
