Jet lag: what it is, how long it lasts and how to get over it fast

You land after a long flight, the sun is shining, and all your body wants is bed. Or it's 3am, the hotel is silent, and you're wide awake. Welcome to jet lag. It's one of the most common side effects of travelling, and almost everyone who has flown across a few time zones knows the feeling.

The good news: jet lag usually clears up within a few days, and there's a lot you can do to make it shorter! Here's everything you need to know, from the symptoms and how long jet lag lasts to practical tips for before, during and after your flight.

What is jet lag?

Jet lag is what happens when your body clock and the clock on the wall stop agreeing. It's a temporary sleep problem that hits when you travel quickly across several time zones.

Your body runs on an internal 24-hour rhythm, called the circadian rhythm. It tells you when to sleep, when to wake up, when to feel hungry and even when to go to the toilet. Daylight is the main signal that keeps this rhythm on track.

When you fly from London to New York, your watch jumps back five hours in one go. Your body clock doesn't get the memo that fast. For a few days it keeps running on UK time, which is why you're starving at odd hours and yawning before dinner.

Good to know: jet lag is about crossing time zones, not about the length of the flight. An 11-hour flight from London to Cape Town barely changes the time, so you'll feel tired but not jet-lagged. A 7-hour flight to New York can knock you out for days.

Jet lag symptoms

The main symptoms of jet lag are all about sleep. According to the NHS, you may notice:

• Trouble sleeping at night and struggling to wake up in the morning
• Tiredness and exhaustion that doesn't go away with a quick nap
• Feeling sleepy during the day, often at the worst possible moment
• Poor concentration and memory, so you forget your hotel room number twice

Jet lag can also mess with your stomach. Indigestion, nausea, constipation and changes in appetite are common. Some people also feel irritable or a little anxious until their body catches up.

How long does jet lag last?

For most people, jet lag lasts a few days. A popular rule of thumb is about one day of recovery for every time zone you cross. So after a five-hour jump to New York, you could feel off for up to five days, although many people adjust faster.

How long it lasts for you depends on a few things:

• How many time zones you cross: two hours' difference is barely noticeable, eight or more can wipe you out for a week.
• Which direction you fly: more on that below.
• Your age: older travellers often take longer to adjust.
• How you slept before the trip: if you board already exhausted, jet lag hits harder.

How long jet lag lasts from London: popular destinations

*Based on the one-day-per-time-zone rule of thumb, using UK winter time.

Is jet lag worse flying east or west?

For most people, jet lag is worse when flying east. Your natural body clock runs slightly longer than 24 hours, so it finds it easier to stay up later than to go to bed earlier.

Flying west, from London to New York, you gain hours. You just stay up a bit later, which your body handles fairly well. Flying east, from London to Dubai or Bangkok, you lose hours. You have to fall asleep when your body thinks it's still the afternoon, and that's much harder.

How to avoid jet lag: what to do before you fly

You can't completely prevent jet lag, but a bit of planning in the days before your trip can take the edge off.

• Shift your sleep gradually: a few days before you leave, go to bed and get up an hour or two earlier (flying east) or later (flying west). Your body will be partly adjusted before you even board.
• Get plenty of rest: starting a long trip already sleep-deprived is the fastest way to a rough first week.
• Pick your flight times wisely: if you can, choose a flight that lands in the late afternoon or evening. It's much easier to stay awake for a few hours and then go to bed than to face a full day after a night flight.
• Plan a soft landing: avoid scheduling an important meeting or a big day out for the first morning after you arrive.
• Pack your sleep kit: an eye mask, earplugs or noise-cancelling headphones and a travel pillow belong in your hand luggage.

On the plane: how to beat jet lag in the air

The flight itself is your chance to start living on destination time.

• Set your watch to local time as soon as you board, and think in that time zone from then on.
• Sleep if it's night at your destination, and try to stay awake if it's daytime there. Need help nodding off? Read our tips on how to sleep well on a plane.
• Drink plenty of water: cabin air is very dry, and dehydration makes tiredness and headaches worse.
• Go easy on alcohol and caffeine: that free glass of wine may help you doze off, but it ruins the quality of your sleep. The NHS warns both can make jet lag worse.
• Keep moving: stretch in your seat and walk up and down the aisle every hour or two. It helps your circulation and keeps you from feeling stiff on arrival.
• Eat light: heavy airline meals at odd hours don't help your stomach adjust. If you can, eat in line with mealtimes at your destination.

How to get over jet lag fast after you land

Once you've arrived, the goal is simple: get your body clock onto local time as quickly as possible.

• Switch to local time straight away: eat, sleep and wake up according to the clock at your destination, not the one back home.
• Get outside in daylight: natural light is the strongest signal for your body clock. A walk in the morning sun is one of the best jet lag remedies there is.
• Avoid long naps: if you really can't keep your eyes open, limit yourself to a 20-minute power nap before mid-afternoon. A three-hour nap will keep you up all night.
• Set an alarm: it's tempting to sleep in, but waking up at a normal local time helps you reset faster.
• Stay active: light exercise during the day helps you feel more awake and sleep better at night.

What about melatonin for jet lag?

Melatonin is a hormone your body releases in the evening to tell your brain it's time to sleep. Melatonin tablets are often marketed as a jet lag cure, but the NHS doesn't recommend them for jet lag because there isn't enough evidence that they work. In the UK, melatonin is only available on prescription. If you're considering it, speak to your GP or pharmacist first.

Good to know: on a short trip of two or three days, it can be easier to stay on your home time. That way you don't have to adjust twice.

Delayed flight made your jet lag worse? You may be owed compensation

Here's something most tired travellers don't realise. You can't claim compensation for jet lag itself, but you may be able to claim for the delay that made it worse.

A long delay throws all your careful planning out of the window. You land in the middle of the night instead of the evening, miss your connection, or spend hours stuck at the gate instead of in bed. That's not just frustrating: it can also be worth money.

If your flight is covered by UK261 or EU261 (flights departing the UK or EU, or arriving there on a UK or EU airline), you may be entitled to €250 to €600 per passenger when:

• You reached your final destination more than 3 hours late
• Your flight was cancelled less than 14 days before departure
• You missed a connecting flight on the same booking because the first flight was late
• And the airline was at fault, for example because of a technical problem or a staff shortage

On top of that, if you're stuck at the airport for a long time, the airline must look after you with food, drinks and, if needed, a hotel for the night. That's called the right to care, and it applies whatever caused the flight delay.

Check now if you're entitled to compensation. Flights from up to 6 years ago could still be eligible!

Frequently asked questions about jet lag

What is jet lag? Jet lag is a temporary sleep problem that happens when you fly across several time zones. Your body clock stays on home time for a while, which causes tiredness, poor sleep and stomach trouble.

How long does jet lag last? Usually a few days. A common rule of thumb is around one day per time zone crossed, but many people recover faster, especially when flying west.

Is jet lag worse going east or west? For most people, flying east is harder. Your body finds it easier to stay up later than to fall asleep earlier.

How do you get over jet lag quickly? Switch to local time immediately, get outside in daylight, avoid long naps and drink plenty of water. Staying off alcohol and caffeine on the flight helps too.

Does melatonin help with jet lag? The NHS doesn't recommend melatonin for jet lag because there isn't enough evidence that it works. In the UK it's only available on prescription, so ask your GP first.

Can I claim compensation for jet lag? Not for jet lag itself. But if your flight was delayed by more than 3 hours, cancelled, or you missed a connection, you may be entitled to €250 to €600 under UK261 or EU261.