Chronotypes: Larks, Owls, and How Much You Can Actually Change

Summary

Your chronotype — whether you run early (lark) or late (owl) — is a **real, partly-inherited biological trait** written in the tempo of your clock genes, not a measure of discipline; eveningness is genuinely associated with worse metabolic, mood, and mortality outcomes, **but** the best causal evidence says most of that "owl disadvantage" is the cost of forcing an evening clock onto a society built on lark time (mediated by social jetlag, sleep restriction, and worse health behaviours), not the clock being intrinsically toxic — and you can **nudge** your phase one to two hours earlier with mor