Chronotype and Health Outcomes: An Update

Abstract Purpose of review To deliver an updated review on chronotype in association with health outcomes. A key question is whether disease risks differ by chronotype, and if they were, by which mechanism. Recent findings All those conditions and diseases studied thus far that do differ between the chronotypes are more common among the evening-oriented individuals, such as irregular or deprived sleep, depressive symptoms or mood disorders, insomnia symptoms, and type 2 diabetes. However, biobank cohort studies show that also individuals with the morning-oriented preference if having late timing of behavior, i.e., being misaligned may develop de novo hypertension and circulatory disorders more often than those having the intermediate chronotype. Associations of chronotype with disease and premature mortality have been mediated partially, but not in full, by health behaviors such as unhealthy dietary intake, physical inactivity, alcohol use or smoking. Summary There is a growing body of literature on health hazards as associated with chronotype, and that those associated with eveningness remain even after accounting for sleep duration and quality, suggesting that chronotype may confer risk beyond insufficient sleep alone. The current data also suggest that individuals having the evening-oriented preference or late chronotype tend to die younger than others in a population.