Social Jetlag: The Weekday/Weekend Clock Mismatch

Summary

Social jetlag is the **measurable mismatch between your body clock and your social schedule** — the shift in your sleep midpoint between work days and free days — and it is a real, prospectively-tracked signal **associated** with higher BMI, worse metabolic markers and more depression, **but** the evidence is almost entirely observational and tangled up with chronotype, social disadvantage and health behaviours, so the honest move is to **shrink the weekday/weekend swing by anchoring a consistent wake time and front-loading morning light**, not to moralise being a night owl in a lark-built wor