At a glance
What is jet lag?
A temporary mismatch between your body clock and local time after flying quickly across time zones. The CDC counts it as a sleep disorder once at least two time zones are crossed. It brings poor sleep, daytime tiredness and poor concentration, and sometimes stomach upsets.
The CDC's Yellow Book describes jet lag as a sleep disorder caused by rapid travel across time zones, which leaves the internal biological clock temporarily out of step with local time; to meet the diagnosis, at least two time zones must be crossed[1]. The NHS lists the main symptoms as difficulty sleeping at bedtime and waking in the morning, tiredness, difficulty staying awake during the day, poor sleep and problems with concentration and memory, with indigestion, nausea, constipation, appetite changes and mild anxiety in some people[2].
How long does it take to adjust?
The NHS says jet lag usually improves within a few days. The CDC puts the body clock's pace at about 1.5 hours a day after flying west and 1 hour a day after flying east, so the more time zones, the longer it takes, and the return east is slower.
The CDC gives adaptation rates of approximately 1.5 hours a day for westward travel and 1 hour a day for eastward travel[1]. Applied to a common trip from the UAE, which is four hours ahead of GMT[4], it looks like this:
Why is flying east harder?
Because the body clock runs slightly longer than 24 hours, so it is easier to push sleep later than to bring it earlier. Flying west asks you to stay up later, which the clock tolerates; flying east asks you to sleep earlier, which it resists.
The CDC explains that the natural circadian rhythm is a little longer than a day, which makes delaying sleep easier than advancing it; westward travel works with that tendency and eastward travel against it[1]. From the UAE, Europe and the Americas lie west and East Asia and Australia lie east, so the return from London or New York is the harder half of the trip.
What can you do before you fly?
Start moving your sleep towards the destination's hours. The CDC says shifting sleep by an hour a day for the two or three days before a trip, later for westward travel and earlier for eastward, may shorten the adjustment. The NHS also advises getting plenty of rest before you go.
- Shift your sleep one hour later a day before flying west, or one hour earlier a day before flying east, for the two or three days before the trip[1].
- Get plenty of rest before you travel, going to bed and getting up closer to the times of your destination[2].
- For a trip of two or three days, the NHS suggests keeping to your usual schedule so you do not have to readjust when you come home[2]; the CDC advises the same for trips of less than two days[1].
What should you do on the plane?
Drink plenty of water, move about the cabin, and sleep if it is night-time where you are going. The NHS advises against too much caffeine or alcohol, which can make jet lag worse, and suggests an eye mask and earplugs if they help you sleep.
What helps most once you arrive?
Light, timed to the direction you flew, and local bedtimes. After flying east, the CDC advises bright light in the morning and avoiding it in the evening; after flying west, the opposite. The NHS adds: switch to the new schedule at once, go outside in daylight, and sleep only at night.
Should you take melatonin or sleeping tablets?
The NHS says medicines are not usually needed for jet lag, and that melatonin is not recommended on the NHS for it because there is not enough evidence that it works. The CDC's guidance for clinicians discusses melatonin and sleep medicines; that is a conversation to have with a doctor.
The two sources differ in emphasis. The NHS says melatonin tablets are not recommended on the NHS for jet lag, for lack of evidence[2]. The CDC's chapter, written for health professionals, discusses melatonin and prescription sleep medicines, and warns that because melatonin is not regulated by the US Food and Drug Administration, the amount in a product may differ from its label[1]. We do not give doses: ask a doctor.
If you do travel with medicine, check the rules for bringing it into the countries on your route; our guide to travelling with medicines into and out of the UAE links the official sources.
Questions travellers ask
How long does jet lag last?
The NHS says it usually improves within a few days[2]. The CDC puts adjustment at about 1 hour a day after flying east and 1.5 hours a day after flying west[1].
Is jet lag worse flying east or west?
East. The body clock finds it easier to delay sleep than to advance it, the CDC explains, so westward travel is easier[1].
Does melatonin help with jet lag?
The NHS does not recommend melatonin for jet lag because there is not enough evidence that it works[2]; the CDC's clinical guidance discusses it[1]. Ask a doctor before taking it.
Should I sleep on the plane?
The NHS suggests sleeping if it is night-time at your destination[2].
Sources
The desk opened each source on the date shown. Rules, fees and timetables change: check the official source before you travel.
- [1]Jet Lag Disorder (CDC Yellow Book 2026, published 23 April 2025) — US Centers for Disease Control and Prevention (CDC). Accessed 26 September 2026
- [2]Jet lag (page last reviewed 31 May 2023) — NHS. Accessed 26 September 2026
- [3]When do the clocks change? — GOV.UK. Accessed 26 September 2026
- [4]Fact sheet — The Official Portal of the UAE Government (u.ae). Accessed 26 September 2026
Published 26 September 2026 · Updated 29 September 2026
Seen something wrong or out of date? Write to trade@nwp.ae and the desk will check it against the source.
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