Circadian rhythms, sleep and cognitive skills

Blavatnik School of Government Working Paper
Osea Giuntella
Wei Han
Fabrizio Mazzonna
Circadian rhythms, sleep and cognitive skills. Evidence from an unsleeping giant.

This working paper focuses on the effects of sleep disturbances in countries undergoing rapid economic transformations and which face the public health challenges associated with economic development.

Using differences in sunset time across Chinese cities, the paper exploits the relationship between circadian rhythms and bedtime to identify the effects of sleep. The authors find large positive effects of sleep duration on cognitive skills (numerical and mental intactness scores) of workers in China aged over 45 years. The results are driven by employed individuals living in urban areas, who are more likely to be constrained by rigid working schedules.

The authors also show evidence that sleep duration reduces the likelihood of reporting depression symptoms and of the cognitive decline associated with ageing. They find that interventions along this direction may be particularly beneficial in developing countries with an increasingly ageing population and that there is a positive relationship between sleeping duration and economic performance.

This BSG paper was written in conjunction with Blavatnik School Working Paper 007, “If you don’t snooze you lose health and gain weight: evidence from a regression discontinuity design.” Together, they analyse the effects of sleep deprivation and the conflict between our biological needs and our social schedules. Both papers highlight the importance of developing a public awareness about the negative effect of sleep deprivation and suggest that reshaping social schedules in ways that promote sleeping may have non-trivial effects on health. While working schedules respond to economic incentives and returns to coordination, their costs in terms of negative effects on health and human capital should not be underestimated.