The effects of sleep duration on child health and development

Abstract

This paper studies the extent to which sleep duration causally affects health, cognitive and non-cognitive development in children and adolescents. Using over 50 thousand time use diaries from two cohorts of Australian children spanning over 16 years, we first document that children sleep significantly less on days with longer daylight duration, partly by going to sleep later and waking up earlier. We then exploit variations in local daily daylight duration measured on pre-determined diary dates across the same individuals through time as an instrument in an individual fixed effects regression model to draw causal estimates of sleep duration on a comprehensive set of child development indicators. Our results show that sleeping longer improves selected general developmental, behavioural and health outcomes in children and adolescents. By contrast, sleeping more statistically significantly increases their BMI scores, mainly by increasing the risk of being overweight. Moreover, while the impact of sleep duration on general and behavioural outcomes is more pronounced for females or older individuals, the effect on BMI is largely driven by males. The results indicate a null or relatively small positive impact of sleeping longer on cognitive skills.

Note:
Funding Declaration: This research was partly funded by the Australian Research Council Centre of Excellence for Children and Families over the Life Course (#CE200100025). The study is conducted in partnership between the Department of Social Services (DSS), the Australian Institute of Family Studies (AIFS) and the Australian Bureau of Statistics (ABS). The findings and views reported in this paper are those of the author and should not be attributed to the DSS, the AIFS or the ABS.

Conflict of Interests: We (as authors) would like to declare that we have no relevant or material financial interests that relate to the research described in this paper.

Ethical Approval: This paper uses secondary datasets. It does not involve any human or animal trials. As such, there is no need to obtain an Ethical approval for this paper.

Keywords: Sleep; Time Allocation; Circadian Rhythms; Human Capital; Child Development