A study by the Autonomous University of Barcelona (UAB in Spanish) and Ramón Llull University have researched the relationship between the sleeping habits, hours slept, and academic performance of children aged between six and seven years of age. Experts have found that sleeping less than nine hours, going to bed late and no bedtime routine generally affects children's academic skills. "Most children sleep less than is recommended for their intellectual development, which is hindered（阻碍） because the lack of sleep cannot be recovered. This is the first Spanish study that proves that losing out on hours of sleep and bad habits affect schoolchildren's academic performance," stated Ramón Cladellas, researcher at the Faculty of Psychology at the UAB.

The study's authors, published in the journal Cultura y Educación, assessed a total of 142 primary schoolchildren (65 girls and 77 boys) from different schools and which did not have any sleep-related pathological changes（病变） . Parents were asked to fill out a questionnaire, concerning the children's habits and number of hours slept per night. The experts also assessed a series of academic skills: communicative, methodological, transversal and specific.

"Although the sample of children sleep almost 8 hours, their sleeping habit shows us that 69% return home after 9pm at least three evenings a week or they go to bed after 11pm at least four nights a week. As such, pupils that sleep 8 or 9 hours have a worse performance than those that sleep 9 or 11 hours," the experts pointed out.

"Taking into account the results obtained, we believe that more than 9 hours sleep and a nightly routine favours academic performance," added Cladellas.

Losing out on hours of sleep and bad habits produced negative effects, especially on more generic skills (communicative, methodological and transversal) which are essential for academic performance. However, there is a lesser effect on the specific skills, more related to cognitive aspects, such as memory, learning and motivation, and they are seen to be more altered by irregular sleep patterns.

"To this end, the lacking hours of sleep distorts children's performance in linguistic knowledge, grammar and spelling rules, and key aspects in the organisation and comprehension of texts, to name a few examples. They are basic skills, meaning that if the pupil, due to a lack of sleep, develops problems in this area, it could have a repercussion on all subjects," explained Cladellas.

The authors concluded that maintaining a healthy sleep pattern at this age contributes to positive cognitive development. They suggest that parents attend prevention programmes to become more aware of the matter.

"Nowadays, there is great concern because children are glued to the television, computers, and videogames, but the same importance is not given to them going to bed at the same time every night," concluded Cladellas.