Sleeping Investment: A Life-Cycle Hypothesis

This paper develops and tests a life-cycle hypothesis of sleep investment. Motivated by evidence from psychology, aging, and sleep research that the consequences of insufficient sleep become increasingly severe with age, we argue that individuals facing stronger productivity incentives should increasingly preserve sleep as they age. We formalize this idea in a simple life-cycle framework in which sleep is a productive activity that competes with work and leisure for time. We test the framework using longitudinal data from the National Longitudinal Study of Adolescent to Adult Health (Add Health). We focus on adolescent physical attractiveness and college education as two characteristics associated with occupational sorting and long-run productivity incentives. While both characteristics exhibit little association with sleep duration in early adulthood, their relationships with sleep become increasingly positive over the life cycle. Attractive individuals and college graduates experience substantially less negative declines in sleep duration with age and increasingly sleep longer relative to their counterparts in later adulthood. Additional analyses show that these patterns are strongest among workers and are not readily explained by mental health, sleep difficulties, social participation, or reverse causality through sleep affecting later attractiveness. More broadly, the findings suggest that differences in long-run productivity incentives contribute to divergent sleep trajectories over adulthood and support a life-cycle perspective on sleep investment.