Getting too little sleep in early childhood is linked to cognitive and behavioural problems years later, a US study suggests.

Parents and teachers reported more problems in seven-year-olds who didn’t get enough sleep during their toddler and preschool years, compared to peers who got an age-appropriate amount of sleep during those early years.

“Children who aren’t getting the recommended amount of sleep have more difficulties with attention, with emotional control, with reasoning, with problem-solving, and also have behavioural problems,” lead author Elsie Taveras said.

What we found was that insufficient sleep in children was associated with poorer executive function and behaviour

“What we found was that insufficient sleep in children was associated with poorer executive function and behaviour,” said Dr Taveras, who is chief of general paediatrics at Massachusetts General Hospital for Children in Boston.

Dr Taveras and her colleagues analysed data on 1,046 children from a study that followed them from before birth. As part of the study, researchers had asked mothers how long the kids slept at age six months, three years and seven years. The mothers also filled out health questionnaires every year.

Insufficient sleep was defined as less than 12 hours during infancy, less than 11 hours for three- and four-year-olds and less than 10 hours for five- to seven-year-old kids.

Mothers and teachers were asked to evaluate each child's executive function and behaviour using questionnaires when the kids were seven years old.

Children who slept less than 10 hours per day at ages three to four years had lower scores from both mothers and teachers compared to kids who usually slept longer. The results were similar for five- to seven-year-olds who got less than nine hours of sleep each night.

Sleep duration between six months and two years old was not linked to scores at age seven, according to the report in Academic Pediatrics.

“(The study) adds to a building literature that is suggesting at least that having sleep problems early in life are predictive of behavioural and, in other populations, cognitive problems later,” Dean Beebe, a paediatric neuropsychologist at Cincinnati Children’s Hospital Medical Center who wasn't involved in the study, said.

“And it is overall consistent with what we've seen in other studies in different age ranges,” said Dr Beebe.

“Having a parent do the sleep rating and then having both the parent and also a teacher do the behavior ratings actually is a really big strength of the study,” he added.

When it comes to sleep, Dr Beebe said he would offer parents three pieces of advice. First, is to take a look and see what is the generally recommended amount of sleep for their kids by checking with the National Sleep Foundation or the American Academy of Sleep Medicine.

"Number two is to pay attention to your child because some kids need more (sleep) and some kids need less,” he said. The third thing is to establish a daily schedule that is sensitive to the child's needs, and also includes routines, Dr Beebe said.

The more chaotic and the less predictable that sleep schedule, the more difficulty the kids tend to have with sleep

"The more chaotic and the less predictable that sleep schedule, the more difficulty the kids tend to have with sleep," he said.

The bedtime routine should involve a winding down period with relaxing activities such as reading a bedtime story, Beebe added. “It seems old fashioned but it's very calming, it's very connecting. It can be very soothing, and it's very predictable,” he said.