Sleep may be even more critical for children than previously realised, according to new research.
Researchers from The Ohio State University found that children aged three to five who regularly went to bed before 8pm were less likely to be obese as teenagers.
They found delaying a child’s bedtime until 9pm doubles their chances of becoming obese.
Lead study author, Dr Sarah Anderson, said the findings “reinforce the importance of establishing a bedtime routine”.
“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,” she said.
The project followed babies born in 10 different US cities in 1991.
Dr Anderson divided bedtimes into three categories: 8pm or earlier, between 8pm-9pm and after 9pm.
The researchers linked preschoolers’ bedtimes to obesity when the children were teenagers, at an average age of 15.
Just one in 10 of the children with the earliest bedtimes were obese as teenagers, compared to 16% of children who went to bed between 8 and 9pm.
Of children with the latest bedtime (after 9pm), 23% were found to be obese by the time they were 15.
Dr Anderson said she focused on bedtimes because they have a greater impact on the duration of sleep than wake times, over which parents have less control.
“It’s important to recognise that having an early bedtime may be more challenging for some families than for others,” she said.
“Families have many competing demands and there are tradeoffs that get made. For example, if you work late, that can push bedtimes later in the evening.”
Commenting on the study, Vicki Dawson, founder and CEO of The Children’s Sleep Charity, told The Huffington Post UK: “Sleep is vitally important to support children’s development and we welcome research that explores the impact of sleep deprivation on children’s physical, emotional and mental wellbeing.
“Establishing bedtime routines is important to encourage good sleep habits and to prevent sleep issues developing. Children who sleep well are more able to fulfill their potential and lead healthy lives.
“Obesity in childhood is a significant concern and the important role that sleep plays in weight gain needs to be recognised. It is vital that an holistic approach is taken to childhood health and specialist support made available to families experiencing sleep issues”