What to know about jet lag in travellers

After crossing time zones, the brain's sleep-wake rhythm may still follow the departure location. This can cause daytime sleepiness, early waking, difficulty falling asleep, poor concentration, irritability, headache and appetite changes. The direction and number of time zones crossed, the timing of light exposure and sleep lost during the journey all influence how disruptive it feels.

Jet lag is usually a short-lived adjustment problem, but fatigue can create practical risks. It may affect driving, childcare, hiking, swimming or decisions made soon after arrival. Plan a gentler first day when possible.

Begin shifting sleep towards the destination schedule when your itinerary allows, without becoming severely sleep deprived. On the flight, drink water, move your legs regularly and use the destination clock to plan rest. On arrival, spend time in suitable daylight, eat at local times and stay awake until a reasonable local bedtime. A brief nap may help, but a long late nap can delay adjustment.

Keep caffeine earlier in the local day and avoid using alcohol as a sleep aid. Check with a pharmacist before taking melatonin, antihistamines or sleeping tablets, especially if you have a medical condition or take other medicines.

Arrange medical advice if symptoms are severe, do not ease as your sleep schedule normalises, or repeatedly interfere with work and daily safety. Seek urgent help for fainting, chest pain, severe breathing difficulty, confusion or new weakness. A persistent sleep problem may have another cause and deserves proper assessment.

Ask how to schedule light and sleep for your journey, whether a sleep aid is safe for you, and how to protect alertness during driving or demanding activities. Share your destination, travel direction, usual sleep pattern and regular medicines.