Sunset Time and the Health Effects of Social Jetlag Evidence from US Time Zone Borders

This paper uses a spatial regression discontinuity design to identify the health effects of the misalignment between social and biological time induced by different sunset times and the fact that social schedules are not responsive to solar cues. Exploiting the discontinuity in the timing of natural light provided by the existence of time zones, we find that being exposed to more light in the evening has negative effects on sleep duration, increases obesity and diabetes prevalence, and the likelihood of reporting any cognitive impairment. Our results suggest that sleep is the main mechanisms explaining the effects on health and cognitive outcomes.