The NHS describes it as your normal sleep pattern being disturbed after a long flight. It usually improves within a few days as your body adjusts to the new time zone.

How long does jet lag last?

The NHS says it often improves after a few days. The CDC gives an average adaptation of 1.5 hours a day after a westward flight and 1 hour a day after an eastward flight.

Is jet lag worse flying east or west?

The CDC says westward travel is easier to adapt to than eastward travel. The NHS page does not split its advice by direction.

Can jet lag be prevented?

The NHS says jet lag cannot be prevented, but there are things you can do to reduce its effects, such as drinking water on the flight and getting daylight after you land.

Should I sleep during the day after I land?

The NHS says not to sleep during the day and to sleep only at night time, and to set an alarm to avoid oversleeping in the morning.

What helps on the plane?

The NHS lists drinking plenty of water, stretching and walking around the cabin, sleeping if it is night time at your destination, and using an eye mask and earplugs if they help. It says too much caffeine or alcohol can make jet lag worse.

Do I need to adjust to the new time zone on a short trip?

The NHS says that on a trip of 2 to 3 days you could keep your usual eating and sleeping times. The CDC says to avoid adapting for trips of less than 2 days.

Can jet lag upset my stomach?

Yes. The NHS lists indigestion, nausea, constipation and changes in appetite among the symptoms, alongside tiredness, drowsiness and problems with concentration and memory.

Jet lag: how to beat it on long-haul flights from the UK

A. FruchardCo-founder & CEOLast updated: 8 November 2026

Jet lag is a disturbed sleep pattern after a long flight, and the NHS says it usually improves within a few days as your body adjusts to the new time zone. The NHS also says jet lag cannot be prevented, but there are things you can do to reduce its effects.

Direction matters. The US Centers for Disease Control and Prevention (CDC) says in its Yellow Book that westward travel is easier to adapt to than eastward travel. From the UK, flights to North America and the Caribbean head west, and flights to India and East Asia head east. This guide follows the order of the trip: before the flight, during it, then after you land.

We pass on what the NHS and the CDC publish, as each states it, with the date we read it, and we add no medical advice of our own. Questions about your own health are for a doctor or a pharmacist, not a travel guide.

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Every guide on hellosafe.co.uk is written from official sources: GOV.UK and the Foreign, Commonwealth & Development Office, and the embassies and immigration services of each destination. Each fact is checked on the date shown under its table, and the page is updated when a rule changes. No airline, tour operator or visa service pays for a place in our guides.

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Yes, according to the CDC. Its Yellow Book chapter on jet lag says westward travel is easier to adapt to than eastward travel, and gives an average adaptation rate of 1.5 hours a day going west against 1 hour a day going east. The body clock catches up more slowly after an eastbound flight.

Which direction is easier
Westward or eastward
What the CDC Yellow Book says
Westward travel is easier to adapt to than eastward travel
Average adaptation
Per day at the destination
What the CDC Yellow Book says
1.5 hours a day for westward travel, 1 hour a day for eastward travel
Before you fly
Sleep timing
What the CDC Yellow Book says
Shift sleep toward the destination time zone in the days before the trip: 1 hour later per day for westward travel, 1 hour earlier per day for eastward travel
Early-morning light
Eastward
What the CDC Yellow Book says
Get bright light in the early morning: open the window shade and avoid dark sunglasses
Early-morning light
Westward
What the CDC Yellow Book says
Avoid bright light in the early morning: close the window shade and wear dark sunglasses

What	What the CDC Yellow Book says
Which direction is easier Westward or eastward	Westward travel is easier to adapt to than eastward travel
Average adaptation Per day at the destination	1.5 hours a day for westward travel, 1 hour a day for eastward travel
Before you fly Sleep timing	Shift sleep toward the destination time zone in the days before the trip: 1 hour later per day for westward travel, 1 hour earlier per day for eastward travel
Early-morning light Eastward	Get bright light in the early morning: open the window shade and avoid dark sunglasses
Early-morning light Westward	Avoid bright light in the early morning: close the window shade and wear dark sunglasses

The CDC chapter is written for health professionals. The page is dated 23 April 2025.Sources: CDC Yellow Book, Jet Lag Disorder. Checked on 1 November 2026.

The NHS page on jet lag does not split its advice by direction. It refers to the time zone you are travelling to, and the advice on the plane and after landing below comes from it. The direction-specific lines in the table come from the CDC alone.

The CDC also says its diagnostic criteria for jet lag disorder require travel across at least two time zones, and it lists the number of time zones crossed as a risk factor.

The NHS has no separate section on the days before a flight, but it does say to get plenty of rest before you travel, and it suggests moving your bedtime and wake-up time toward your destination's time zone. The CDC is more specific: it recommends shifting sleep toward the destination time zone in the days before the trip, with an example of 1 hour later per day for westward travel, or 1 hour earlier per day for eastward travel.

Your documents and entry rules are the other thing to settle early, so they do not eat into those days. Which countries need a visa for a British passport is on our entry requirements for British passport holders page.

The NHS gives a short list of things to do and one thing to avoid while you are in the air. Most of it is about water, movement and when you try to sleep.

Water: The NHS says to drink plenty of water.
Movement: Keep active by stretching and regularly walking around the cabin.
Sleep at the destination's night: Try to sleep if it is night time at your destination.
Eye mask and earplugs: Use them if they help you sleep.

Caffeine and alcohol: The NHS says too much of either can make jet lag worse.

The sleep rule is tied to the clock you are heading for, not the one you left. If it is the middle of the day where you are going, the NHS does not ask you to sleep. The full list is on the NHS jet lag page.

Change your sleep schedule to the new time zone as quickly as possible: that is the NHS's first instruction for the first days at your destination. It adds three more, and one thing to avoid.

New schedule: Change your sleep schedule to the new time zone as quickly as possible.
Alarm: Set an alarm to avoid oversleeping in the morning.
Daylight: Go outside during the day, because natural light helps your body clock adjust.

Daytime sleep: The NHS says not to sleep during the day, and to sleep only at night time.

The NHS gives the general rule on light, which is to go outside in the day. The CDC adds the timing by direction: bright light in the early morning after an eastbound flight, and none in the early morning after a westbound one. It also says that evening light tends to delay the body clock.

The NHS lists problems with sleep first, then daytime effects, then thinking and the stomach. They are usually temporary.

Sleep
Difficulty sleeping at bedtime and waking in the morning, and poor quality sleep.
Daytime
Tiredness and daytime drowsiness.
Thinking
Problems with concentration and memory.
Stomach and appetite
Indigestion, nausea, constipation and changes in appetite.
Mood
Mild anxiety.

Because concentration is on that list, it helps to know what your first day abroad asks of you. If it includes driving, our driving abroad guide covers the licence and the rules of each country.

The NHS says medicines are not usually needed for jet lag. Sleeping tablets may help with severe insomnia but can be addictive, so they should only be used for a short time. Melatonin is a hormone your body releases in the evening to signal sleep time, and the NHS says melatonin tablets are not recommended on the NHS for jet lag because there is not enough evidence to show they work.

Other health bodies treat melatonin differently: the CDC Yellow Book discusses it as a way to shift the body clock. We give no dose and no product advice on this page. The NHS page and the CDC chapter are both linked so you can read each in full.

The NHS says that on a trip of 2 to 3 days you could keep your usual eating and sleeping times, so that you do not have to change your schedule again when you get back. The CDC sets a shorter limit: for trips of less than 2 days, it says to avoid adapting to the new time zone.

Both pages describe the same idea from two thresholds, and each is quoted as its publisher wrote it. A trip of exactly 2 days sits on the edge of both.

Jet lag is one check among several. Entry rules, any visa and your documents come first: they decide whether you travel at all. Our travel tips for UK travellers collect the other checks worth making before you go, and the entry requirements guide covers the visa side for British passport holders.

The NHS describes it as your normal sleep pattern being disturbed after a long flight. It usually improves within a few days as your body adjusts to the new time zone.
The NHS says it often improves after a few days. The CDC gives an average adaptation of 1.5 hours a day after a westward flight and 1 hour a day after an eastward flight.
The CDC says westward travel is easier to adapt to than eastward travel. The NHS page does not split its advice by direction.
The NHS says jet lag cannot be prevented, but there are things you can do to reduce its effects, such as drinking water on the flight and getting daylight after you land.
The NHS says not to sleep during the day and to sleep only at night time, and to set an alarm to avoid oversleeping in the morning.
The NHS lists drinking plenty of water, stretching and walking around the cabin, sleeping if it is night time at your destination, and using an eye mask and earplugs if they help. It says too much caffeine or alcohol can make jet lag worse.
The NHS says melatonin tablets are not recommended on the NHS for jet lag because there is not enough evidence to show they work. We give no dose or product advice.
The NHS says that on a trip of 2 to 3 days you could keep your usual eating and sleeping times. The CDC says to avoid adapting for trips of less than 2 days.
Yes. The NHS lists indigestion, nausea, constipation and changes in appetite among the symptoms, alongside tiredness, drowsiness and problems with concentration and memory.
The CDC says its diagnostic criteria for jet lag disorder require travel across at least two time zones, and that the number of time zones crossed is a risk factor.