Incidence of Out-of-Hospital Cardiac Arrest on a Postholiday Weekday.

In this nationwide cohort study, a postholiday weekday was associated with a significantly elevated out-of-hospital cardiac arrest incidence in South Korea, particularly after consecutive rest days and among vulnerable populations. These findings support enhanced emergency medical services preparedness, targeted public health messaging during holiday periods, and evaluation of preventive interventions for high-risk populations during postholiday transitions.