What should you know about delayed jet lag?

Delayed jet lag reflects a body clock that has not adjusted to the new time zone, so sleep and alertness can remain disrupted after travel. You may have difficulty sleeping at local bedtime, wake too early, feel sleepy during the day, or develop headache and reduced concentration. Symptoms should gradually ease as your routine and light exposure align with local time.

Travel across time zones changes the timing signals that coordinate sleep, meals and alertness. Cabin fatigue, dehydration, alcohol, stress and an irregular schedule can add to the discomfort. Delayed jet lag is different from a new sleep disorder if it follows travel and improves with adjustment, although persistent symptoms may need another explanation.

Daylight is a strong body-clock cue. The useful timing of outdoor light depends on the direction of travel and the destination, so a travel clinician can help with complex itineraries.

Set your activities, meals and sleep to local time. Get natural light during the destination's daytime, keep the bedroom dark and quiet at night, and use a regular wake time. Drink water, move gently, and avoid alcohol close to sleep. Keep naps short and early if you need one. Do not drive or operate equipment when very sleepy. A clinician can advise whether insomnia management or another treatment is appropriate.

Arrange medical advice if sleep disruption or daytime sleepiness is worsening, prevents safe driving or work, or does not begin improving after your travel recovery period. Seek urgent help for chest pain, severe breathlessness, fainting, new weakness, confusion or a sudden severe headache, because these are not typical jet-lag symptoms.

Ask how to time light exposure for your route, whether a medicine or supplement is suitable, and whether another condition could explain the symptoms. Mention your departure and arrival times, sleep pattern, caffeine or alcohol use, and any safety-sensitive tasks.