Modelling the effects of flight itinerary on jetlag duration

Flight departure and arrival times contribute to the variability of jetlag duration and can reverse the direction of circadian adaptation post-flight. These dynamics are mainly governed by light exposure and sleep timing during and around flights. Statement of Significance This study provides a quantitative analysis of how flight itineraries interact with circadian and sleep physiology to determine jetlag duration. By simulating over 55,000 flights across all time zone transitions, we reveal systematic patterns linking flight timing with adaptation time and the opportunities to minimise circadian disruption through itinerary design and behaviours during and around flights. These findings advance the mechanistic understanding of jetlag and offer actionable insights for travellers and airlines to reduce jetlag burden through optimised flight schedules and personalised strategies.