Early bedtime, better school performance

There is a strong relationship between sleep problems and poor academic performances among adolescents, a new study demonstrates.

The study is published in Journal of Sleep Research, and shows that the less the adolescent sleep -- the worse the grades get on average.

"Our findings suggests that going to bed earlier, and encouraging similar bed- and sleeping times during the week, are important for academic performance," says psychology specialist and first author Mari Hysing at Uni Research in Bergen, Norway.

Hysing and colleagues analysed data from a large population based study conducted in Norway in 2012, including 7798 adolescents from Hordaland county. This survey is called youth@hordaland -- a large and representative sample.

School performance was measured by Grade point average (GPA), and obtained from official administrative registries. The adolescents (aged 16-19) who went to bed between 10 and 11 p.m. had the best grades on average.

Going to bed much later during weekends than weekdays, were also associated with lower GPA.

The new study is a collaboration between researchers from Uni Research, the Norwegian Institute of Public Health, Ørebro University and University of California, Berkeley.

The results underscore the importance of sleep for academic functioning, the researchers point out:

"Academic performance is an important marker for future work affiliation and health. Future studies should investigate further how the association between sleep and school impacts upon future educational status and work affiliation," they write.

After adjusting for sociodemographic information, short sleep duration and sleep deficit were the sleep measures with highest odds of poor performance at school.

Hysing and colleagues only investigated the association between sleep and school performance. When adjusting for non-attendance in school, associations were somewhat reduced, but the link between sleep and GPA was still significant.