What should you know about persistent jet lag?

Crossing time zones makes the sleep-wake rhythm, light exposure, meals and activity occur at unfamiliar times. You may have difficulty sleeping at night, wake earlier than planned, feel sleepy during the day, or notice headache, poor concentration and irritability. Symptoms can be more troublesome after several time-zone changes, eastward travel, irregular schedules or limited sleep during the journey. Jet lag itself is not the same as insomnia, although ongoing sleep disruption can resemble or contribute to it.

Keep track of when you sleep, wake, nap and use caffeine, along with the direction of travel and the date symptoms began. This pattern helps distinguish a body-clock adjustment from another sleep problem.

Use local time for meals, daylight and bedtime as soon as practical. Seek bright outdoor light during the part of the day that matches your intended schedule, keep naps brief and early, and use a quiet, dark bedroom at night. Drink fluids, eat lightly if your stomach feels unsettled, and avoid driving or safety-sensitive work when very sleepy. A travel-health consultation can help plan light exposure and medicines safely for future journeys; do not start sleep aids or melatonin without checking whether they suit you.

A regular wake time is often easier to maintain than forcing sleep. If symptoms continue, an assessment can look for insomnia, medication effects, mood symptoms or another cause of fatigue.

Arrange a medical review when sleep disruption or daytime sleepiness continues after reasonable adjustment time, repeatedly follows travel, or affects work, driving or mood. Seek urgent help for confusion, fainting, severe weakness, chest pain, trouble breathing, or a sudden severe headache. These symptoms need assessment rather than being attributed to jet lag alone.

Ask whether your pattern fits jet lag or another sleep disorder, which light and sleep schedule is appropriate for your route, and whether any medicine or supplement could be worsening sleepiness. Discuss how to manage future flights and when persistent symptoms should be reassessed.