Insights about travel-related sleep disruption from 1.5 million nights of data

The growing adoption of reliable wearable sleep trackers has made it possible to analyze multi-night, objective sleep data from travelers on a scale hitherto not possible. This study was designed to complement previous studies of jet lag and circadian re-alignment conducted under highly controlled laboratory conditions and small-scale field studies typically involving specialist samples such as professional athletes.

De-identified sleep data from 15 days before and after 64 847 trips from 57 240 Oura Ring users were analyzed. Trips were at least 1000 km and originated from North America and Europe. We characterized the evolution of sleep timing, duration, and macro-architecture, considering the influence of number of time zones crossed, direction of travel, and habitual sleep patterns.

Sleep disruption began with curtailed sleep on the night before travel because of early awakening. Sleep duration was shorter during and immediately following travel but returned to within ~12 minutes of baseline after ~2 days. In contrast, changes in sleep timing and sleep architecture were considerably slower to recover, with sleep timing not returning to baseline after 15 days. Sleep disruption was more severe with eastward travel and across more time zones. Interindividual differences in both sleep duration and timing equilibrated with travel.

Both structural and intrinsic circadian factors influence sleep during travel. Sleep homeostatic mechanisms drive recovery of sleep duration quickly although architecture is still compromised. Re-alignment of sleep timing to the new time zone takes significantly longer.