Sleep Regularity

Research summary

• Sleep regularity has emerged as an active and increasingly well-supported area of research, with recent large cohort studies (UK Biobank, MESA) finding that day-to-day consistency of sleep timing predicts cardiovascular disease and mortality risk, in some analyses more strongly than sleep duration itself.
• Multiple systematic reviews from the past few years converge on similar conclusions across cardiometabolic, cognitive, and mortality outcomes.
• This is a comparatively young but rapidly growing evidence base built on large, well-designed cohort studies using objective sleep tracking, which gives reasonable confidence in the association, while randomized trials testing whether improving regularity itself changes outcomes are not yet part of the evidence reviewed here.