Social Jetlag and Related Risks for Human Health: A Timely Review

Abstract

The term social jetlag is used to describe the discrepancy between biological time, determined by our internal body clock, and social times, mainly dictated by social obligations such as school or work. In industrialized countries, two-thirds of the studying/working population experiences social jetlag, often for several years. Described for the first time in 2006, a considerable effort has been put into understanding the effects of social jetlag on human physiopathology, yet our understanding of this phenomenon is still very limited. Due to its high prevalence, social jetlag is becoming a primary concern for public health. This review summarizes current knowledge regarding social jetlag, social jetlag associated behavior (e.g., unhealthy eating patterns) and related risks for human health.

Keywords: chronotype; circadian misalignment; health risk; sleep; social jetlag.

Figure 1

Social jetlag (SJL) and sleep debt-corrected SJL (SJL_SC). Comparison between social jetlag (SJL) calculated as proposed by Wittman et al. [17] and sleep debt-corrected SJL (SJL_SC) as proposed by Jankowski et al. [58]. This schematic representation shows the hypothetical sleep episodes of a late chronotype with an early schedule from Monday to Friday. Bars illustrate sleep episodes, as well as their timing (expressed in local time) and duration, on school/work days (red bars) and free days (green bars). Following the formula proposed by Jankowski et al. [58] (lower part of the illustration), MSW_SC results delayed if compared to MSW due to sleep debt school/work days (red dashed block), while MSF_SC is anticipated if compared to MSF because of the oversleep of free days (green dashed block). Abbreviations: MSF, midsleep on free days; MSW, midsleep on work days; MSF_SC, oversleep-corrected midsleep on free days; MSW_SC, sleep debt-corrected midsleep on work days.