Dr Sarah Jarvis, MBE
Author: Dr Sarah Jarvis, MBE, General Practitioner (GP)

Dr Sarah Jarvis is the Clinical Director of the Patient Platform, an active medical writer, broadcaster, and the resident doctor for BBC Radio 2.

Originally posted: 31st Oct 2022

Whether you are planning to travel to a distant time zone on holiday or find yourself constantly suffering from tiredness, even on short trips, in this article, we’ll cover the meaning of “jet-lagged”, what causes it and how to avoid it.

What is jet lag?

You don’t need to be a jet setter to suffer from jet lag – a single trip across several time zones can leave you feeling exhausted, sluggish, light-headed, anxious, sick or irritable. But the greater the time difference, and the more frequently you change time zones, the greater the risk.

Jet lag usually only occurs when the clocks at your destination are more than three hours different from home.

When you travel west, you ‘lose’ time – in other words, the clocks go back compared to UK time. Travelling west usually leads to less jet lag than travelling east, when you ‘gain’ time and clocks go forward.

One thing to note is that you’ll only be at risk of jet lag if you travel by plane. If you’re travelling by boat, on a cruise holiday say, your body should have time to adjust, and jet lag shouldn’t be an issue.

READ MORE: Do You Need Specialist Travel Insurance for a Cruise Holiday?

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What causes jet lag?

Your brain has an internal body clock, controlled by a part of your brain called the hypothalamus. This part of your brain regulates the production of two hormones linked to alertness and body temperature – melatonin and cortisol. Scientists have worked out that your body clock naturally runs for just over 24 hours. That may be why travelling east (when bedtime comes earlier than it would at home) causes more jetlag than travelling west, when it feels like you’re having a late night.

At night, when your hypothalamus isn’t receiving light signals from your eyes, it tells another part of your brain (the pineal gland) to release melatonin. This release usually starts a couple of hours before you go to bed, which is why you may start to feel drowsy. In daylight, melatonin release drops. The higher your melatonin levels, the better you sleep and the better you concentrate when you’re awake.

Cortisol levels are closely linked to those of adrenaline – the ‘fight or flight’ hormones. These levels tend to rise in the early mornings. Adrenaline makes you feel more alert. For every hour of time, you ‘lose’ or ‘gain’ by crossing time zones, it takes your body’s cortisol levels about a day to get back into sync.

Some people are more prone to jet lag than others, even if they take the same trip. If you’re travelling just for a few days, you may be able to stay fairly close to the UK time. For instance, if you’re going to New York for three days, where the clocks go back by five hours, you could go to bed every evening at 8pm (1am UK time) and set your alarm for 4am (9am UK time). If you’re doing this, keep evening light to a minimum and get out into daylight the moment you can in the morning to avoid your body adjusting.

What are the main jet lag symptoms?

As with all illnesses, jet lag can manifest in one person differently than it might in another; however, some of the main symptoms of jet lag are: 

  • Difficulty sleeping at normal times
  • Poor sleep quality when you can sleep
  • Feeling tired and exhausted when awake
  • Issues with concentration and memory 

In some cases, someone experiencing jet lag might also have dizziness, nausea, indigestion and constipation and mild feelings of anxiety.

How long does jet lag last?

How long jet lag lasts can depend on your circumstances, but it tends to last for no more than a week. Most people will find that their internal clock catches up with their travels in a few days.

If you do find that your symptoms continue for more than a few weeks, you should talk to your doctor.

Jet Lag

How can I avoid jet lag?

Luckily, jet lag is something that you can work to avoid, and there are ways to get over jet lag if you are experiencing it.

Tips to avoid jet lag before your trip

Start adjusting your sleep pattern early

One of the best things you can do to prevent jet lag is to adjust your sleeping pattern before you travel. By doing this, you’ll be starting on the front foot, and your body will already have transitioned to your new time zone.

 If you’re travelling west, this means you’ll need to adjust your internal timings so that your brain believes it’s earlier in the day than it is. A few ways that you can do this include:

  • Try and stay in bright light in the evenings as long as possible.
  • Stay awake and go to bed an hour later every day before your trip for a few days, so that the adjustment is slow rather than sudden.
  • Keep your bedroom dark to try and sleep in later.

If you are travelling east, you should do the opposite and try to go to bed earlier and get up earlier.

Get plenty of rest

You may think that a holiday is a time to rest, but if you can try to unwind before you travel, you’ll be more likely to fend off the symptoms of jet lag. Jet lag tends to be worse if you’re already sleep-deprived, so making sure this is not the case before you set off can make a great difference.

Try technology

The Timeshifter app can be a useful tool to help you adjust your schedule before you leave, and its goal is to connect you with your circadian rhythm.

You’ll be able to enter the details of your travel into the app, and it’ll offer you notifications as prompts on the best actions. Tips include such things as avoiding or seeking natural light; taking naps; staying up; and considering a shot of coffee to raise alertness.

Tips to avoid jet lag whilst you’re travelling

Change your clock

Changing your clock to the time at your destination on the day of your travel can help you mentally shift time zones before you physically do. Just don’t let it confuse your airport timings!

Keep hydrated

Dehydration can make jet lag worse, so staying well hydrated is key. Have plenty of fluids on the plane, but avoid alcohol, as this can dehydrate you.

Consider sleeping

If it’s nighttime at your destination when you’re on the plane, try to get some sleep – booking a window rather than an aisle seat and taking an eye mask and ear plugs may help you to fall asleep, even if other passengers aren’t. 

Think about when you eat

If you can, try to plan your meal times for the time you’ll be eating at your end destination. This is a good way to make your body think the time is different than it is, and it will also set you up for when you land.

Tips for avoiding jet lag after your journey

Utilise caffeine

Caffeine (in coffee, tea, colas and energy drinks) can be very helpful to increase alertness – great if you’re nodding off during the day but counterproductive if it stops you from getting to sleep.

Alternatively, if the clocks have gone forward and you need to sleep earlier than usual, it may be worth avoiding caffeine except on waking and certainly after the early afternoon.

Melatonin treatment

Melatonin tablets are not sleeping pills per se, but have been found to help shift your body clock, and can be particularly effective at adjusting your sleep cycle if you’re travelling east. This medication isn’t routinely available on the NHS, but many pharmacists now sell it after a consultation to check it’s suitable for you. 

The standard dose for jet lag-induced sleep problems (as recommended by the NHS) is 3mg, which can be taken once a day for up to five days. The first dose should be taken when you arrive at your destination, however, it shouldn’t be taken before 8 pm or after 4 am.  


With these tips, you’ll hopefully be able to keep jet lag to a minimum, regardless of the number of time zones you’re travelling through. So, with some planning and some handy sleep aids such as a sleep mask and a useful app, you’ll be able to make the most of your time away.

Planning a trip? With Medical Travel Compared, you can get yourself the best deal on the best cover possible for your situation.

If you are looking for more travel articles and advice, be sure to check out. 

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You must have a permanent UK address, have lived in the UK for the last 6 months and be registered with a medical practitioner in the UK. All trips must start and end in the UK and you must purchase the insurance before you depart for your first trip.

Single Trip insurance is for one-off, individual trips and will cover your specified travel dates. This is usually up to 45 days; however, some insurance providers can cover up to 94 days. If you’re not a frequent traveller, single trip cover is a great option and will likely be cheaper than an annual multi-trip cover.

If you travel 2 or more times a year, annual trip cover may very well save you money. The maximum duration of any trip will always be specified and will vary by provider. But don't worry, when you get a quote, we'll ask you what your maximum trip length is and only show you quotes that match!

A pre-existing is any medical condition for which medical advice, diagnosis, care, or treatment was recommended or received before applying for a travel insurance policy. For some conditions, we'll need to know if they have ever been present, whilst for others if they occurred within a certain period.

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