Abstract:

Social Jetlag (SJL) refers to discrepancies existing in sleep-wake pattern between students’ school days and weekend days (or non-school days), which is mainly resulted by the misalignment of school schedules and circadian rhythms and characterized by a systematic shift in the midpoint of sleep. SJL is widespread among student populations worldwide. Despite growing attention to the adverse health effects of SJL, student-focused research remains fragmented and lacks systematic integration. This review synthesizes the literature on SJL across four domains: determinants, health outcomes, underlying mechanisms, and intervention strategies.

Regarding etiology, this review categorizes the determinants of SJL into three broad domains: endogenous, exogenous, and institutional factors. Endogenous factors (e.g., nocturnal chronotypes, age, and sex) constitute the primary biological basis of SJL; exogenous factors (e.g., 24-hour electricity and internet availability, high-density indoor lifestyles, and the widespread use of electronic devices) provide an enabling environment for its development; and institutional factors (e.g., globally prevalent early school start times) act as key drivers of its emergence. The interplay of these internal and external influences disrupts circadian rhythms in students, ultimately giving rise to SJL and posing substantial risks to their physical and mental health.

Regarding health outcomes, this review delineates the multifaceted impacts of SJL across two domains: physiological and psychological. Physiologically, SJL is significantly associated with obesity, elevated cardiometabolic risk, and diminished sleep quality. Psychologically, SJL is significantly correlated with symptoms of anxiety and depression, declines in cognitive functioning, poorer academic performance, and behavioral issues, including deficits in prosocial behavior, addictive behaviors, and disordered eating patterns. These associations exhibit variations based on gender and age, as well as characteristics of cumulative effects over time, and are particularly pronounced among individuals with nocturnal chronotypes and adolescents.

Regarding mechanisms, circadian disruption induced by SJL first leads to dysregulated expression of core clock genes (e.g., CLOCK and PER), which in turn activates the hypothalamic-pituitary-adrenal (HPA) axis and the renin-angiotensin system, resulting in elevated cortisol levels and autonomic dysfunction. This central pathway further diverges into three downstream routes. At the metabolic level, increased ghrelin, decreased leptin, and reduced insulin sensitivity contribute to obesity and heightened cardiometabolic risk. At the neurobehavioral level, impaired prefrontal cortical functioning, heightened amygdala reactivity, and attenuated dopaminergic signaling jointly give rise to anxiety and depressive symptoms as well as behavioral problems. At the sleep level, delayed sleep phase and the accumulation of sleep debt disrupt slow-wave and rapid eye movement (REM) sleep, impede the restoration of synaptic homeostasis, and ultimately compromise memory consolidation and cognitive control.

Regarding interventions, existing studies have addressed SJL among students from three single perspectives (endogenous, exogenous, or institutional) and have demonstrated modest effectiveness. However, these interventions reveal limited effect sizes, poor long-term sustainability, and insufficiently developed exogenous intervention strategies. To mitigate the progression and exacerbation of SJL in student populations at its source, a technology-empowered four-level intervention system, featuring systematic integration of collaboration among the “government, schools, communities, and families”, is proposed to establish a closed-loop management process comprising four stages: assessment, diagnosis, intervention and follow-up. This system aims to achieve the early identification, warning and intervention of Social Jet Lag among students.

This study makes three primary contributions. First, it extends research on the adverse effects of SJL beyond single outcome variables to a comprehensive synthesis encompassing six domains: obesity, cardiometabolic risk, sleep quality, anxiety and depression, cognitive and academic performance, and behavioral problems, thereby revealing pervasive sex and age-related differences, as well as cumulative effects over time across these outcomes. Second, it elucidates how dysregulation of core circadian clock genes exerts effects via the neuroendocrine system, ultimately leading to widespread impacts on metabolism, sleep, cognition, and behavior. Third, it moves beyond single-component interventions by proposing a four-level intervention system based on collaboration among four key stakeholders. Collectively, this study not only broadens the psychological perspective on circadian health research but also provides a theoretical foundation and practical implications for optimizing school schedules and improving student sleep health policies. Future research should prioritize randomized controlled trials, longitudinal cohort studies, and more rigorous causal inference, while advancing context-specific intervention strategies tailored to the Chinese educational setting.

Key words: Social Jetlag (SJL), physical and mental health, circadian clock, school schedule