A pattern-based approach to assessing sleep-corrected social jet lag

Social jet lag (SJL), i.e. the misalignment between internal biological clocks and social schedules, can negatively impact health. Traditional SJL, defined as the difference in mid-sleep time between workdays and free days, may overestimate misalignment, especially in individuals who extend sleep on free days to offset workday sleep deficits. To refine this measurement, Jankowski proposed sleep-corrected social jet lag (SJLsc), which accounts for variations in sleep duration between workdays and free days. Building on this work, we propose a practical extension of the SJLsc framework that applies a unified rule across seven sleep patterns. Utilizing data from the 2017-2020 National Health and Nutrition Examination Survey (NHANES), we illustrated a step-by-step method for calculating SJLsc. We found that 3.2% of participants were classified into different SJLsc categories (0-< 1.0 h, 1.0-< 2.0 h, and ≥2.0 h) depending on whether Jankowski's method or our approach was used. Continuous SJLsc values from both methods showed high concordance (Spearman's ρ = 0.94). Our approach offers a simple and transparent rule that can be applied consistently across diverse sleep patterns.