Jet lag – why it happens and how to beat it

6th April, 2022 • 9 min read

Jet lag is the feeling of tiredness and confusion that can happen after you’ve been on a long-haul flight. It’s common, and affects millions of people worldwide every year.

It happens when your body finds it difficult to adjust to the time zone of the country you’ve flown to. The more time zones you cross during your flight, the more likely you are to get it.

Because it can affect how well you sleep and how you feel, jet lag can be frustrating, both when you’re travelling and when you get home. But the good news is, it usually only lasts a few days, and can be managed with self-care and a bit of preparation.

We don’t want jet lag to get in the way of your time away, or affect your life when you get back. So here’s what you need to know, including what you can do to reduce the impact of some of the symptoms, and when to see a doctor.

What is jet lag?

You have an internal 24-hour clock, called your ‘circadian rhythm’, which regulates how your body works. It helps to control your sleep-wake pattern, which is normally aligned with daylight – so you feel awake during the day and sleepy when it’s dark.

But jet lag can happen if your internal body clock doesn’t match the 24-hour cycle of day and night at your travel destination. This can happen when you fly to a part of the world that has a different time zone from where you started – and particularly if you cross more than 1 time zone.

Find useful information on other areas of sleep with our

complete Guide

Jet lag symptoms

Although anyone who rapidly crosses time zones can get jet lag, it’s possible that 1 in 3 people don’t get it.

The main symptoms of jet lag are:

  • trouble sleeping or poor sleep quality – it may be hard to fall asleep when you want to, or you may wake up earlier than planned
  • tiredness during the day – you may struggle to stay awake
  • problems with memory and concentration

In some cases, other jet lag symptoms can include feeling sick (

, changes in appetite,

How long does jet lag last?

Unlike travel tiredness (fatigue), which is common after a trip and usually goes away after a good night’s sleep, jet lag symptoms can last until your body clock becomes aligned to the cycle of day and night at your destination.

Key things to know about how long jet lag lasts:

  • symptoms can begin straight after your flight or a few days later
  • you might sleep well on the first night, but then have sleep problems in the next few days
  • symptoms can last from a few days to a few weeks. As a rough guide, it’s thought it can take about 1 day per 1 hour of time difference for your body to readjust. But this varies a lot from person to person

What makes jet lag more likely – or worse?

There are a number of things that can make jet lag more likely or more severe, including:

  • crossing multiple time zones – if you travel through 3 or more time zones, your jet lag is likely to be worse
  • travelling east – delaying your body clock is usually easier than bringing it forward, so jet lag can be worse when you travel east rather than west. North-south flights won’t cause jet lag, as you don’t cross time zones
  • your arrival time – this can affect your body clock. If you’re flying east, jet lag may be worse if you arrive early morning, rather than in the afternoon
  • poor sleep before you fly – not sleeping well in the days leading up to your flight can increase your chances of jet lag
  • drinking
    or caffeine during your flight
    – both these have the potential to disrupt your sleep
  • a history of jet lag – some people are just more likely to get jet lag, so if you’ve had it before you’re likely to get it again

Your science-backed guide to beating jet lag

Before your flight:

  • in the days leading up to departure, get as much sleep as you can
  • a few days before you fly, try to start going to bed at a time closer to when you’ll go to bed at your destination
  • in the hours before flying, avoid alcohol, caffeine and nicotine, as these can act as stimulants
  • when you board, change your watch to match the time at your destination

During your flight:

  • stay as
    as you can
  • avoid eating heavy meals
  • don’t drink alcohol, or keep it to a minimum
  • try to sleep when it will be dark at your destination – use ear plugs and an eye mask to help
  • when you’re not sleeping, keep mobile by stretching and walking around the plane cabin from time to time

On arrival:

  • if you feel sleepy, take a short nap if you can
  • go for a walk during daylight hours – the natural light will help your body clock adjust to your new time zone
  • on your first night in your new time zone, try to get at least 4 hours of sleep
  • set an alarm to avoid oversleeping in the morning
  • if you’ve travelled east over 3 to 8 time zones, try to expose yourself to bright light in the morning and avoid it in the evening. If you’ve travelled west over 3 to 8 time zones, do the opposite – get bright light in the evening and avoid it in the morning

General tips to help you sleep better:

  • avoid eating a heavy meal before going to bed, and try to avoid caffeine, alcohol and nicotine in the 3 hours before bedtime
  • don’t exercise too near to bedtime (but regular physical activity and exercise during the day can help you sleep better at night)
  • try to relax before going to bed – such as by having a bath, doing gentle stretching or reading (try to avoid using a screen to read)
  • make sure your bedroom is comfortable – it should be cool, dark and quiet

Read more about how to get

better sleep

How can a pharmacist help with jet lag?

Your pharmacist can recommend ear plugs and sleep masks for your flight. They may also discuss whether a sedating

could be helpful for you – although these have possible side effects and aren’t usually recommended.

In some countries, you can buy

supplements for jet lag from a pharmacy. Melatonin is a hormone your body makes to help control your sleep patterns. However, there’s limited evidence that melatonin supplements can reduce the effects of jet lag.

In the UK, melatonin for jet lag is only available on prescription, and isn’t usually recommended because it isn’t clear that it’s effective. In most cases, jet lag medication isn’t necessary – your body will adapt quickly, and the tips above should also help.

When to see a doctor about jet lag

Jet lag is a temporary condition, which goes away within a few days or weeks.

But if you fly a lot and find you’re often struggling with jet lag or extreme tiredness, it’s a good idea to see your doctor. If needed, they may be able to refer you to a sleep specialist.

If you’re not sure whether you need to see a doctor, try our

Smart Symptom Checker
to work out what your next step should be.

How is jet lag diagnosed?

Jet lag is usually simple to diagnose by you or your doctor, without the need for any tests.

For a doctor to make the diagnosis, you must have travelled across at least 2 time zones, and have either daytime sleepiness or trouble sleeping (

). If you’ve travelled west, you’re likely to have difficulty staying asleep, while if you’ve travelled east you’re likely to have difficulty falling asleep.

If your sleep problems include snoring and daytime sleepiness, your doctor may recommend some tests to check if you have a condition called

sleep apnoea
. Read more about
how sleep apnoea is diagnosed

Medical treatments for jet lag

Jet lag isn’t permanent, and any symptoms can usually be managed without medical treatment.

Sleeping pills
(hypnotics) aren’t routinely prescribed, but may be helpful if you have short-term insomnia caused by jet lag. A type of sleeping pill known as a ‘Z drug’ has been shown to improve sleep in some travellers, if taken for the first 3 nights after flying.

However, they can be addictive and have other side effects, so they’re not routinely recommended. They should only be used for a very short time if your symptoms are severe, after discussion with your doctor. And although they may help you fall asleep or stay asleep, they don’t help to readjust your body clock.

Your health questions answered

I get very anxious before flying. Is there a treatment for this – and will this make jet lag worse?

Answered by:

Dr Roger Henderson

“It’s common to have a fear of flying or feel anxious when flying. Non-medical treatments include

breathing exercises
cognitive behavioural therapy (CBT)
, while several airlines run ‘fear of flying’ courses, which some people find helpful. But medication may be needed if your anxiety is very severe. Taking low-dose
before flying can be very effective, and won’t cause problems with jet lag or performance after your flight.”

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.