Whether you travel for business or pleasure, chances are you’ve experienced jetlag. Its effects can range from being a little sleepy at the wrong time of day to feeling disorientated and almost flu-like. But what causes us to experience jetlag in the first place?


Dr Vikki Revell of the University of Surrey has been researching jetlag for the past 14 years, and how it affects travellers and shift workers. She says one of the main causes of jetlag is ‘circadian misalignment’, where your body click is out of sync with the sleep/wake cycle you want to be on.

“The reason it happens is your body clock can’t instantly reset,” she says. “It takes about an hour to adjust for each time zone you travel and your body can basically shift about an hour per day. So for you to fully adapt to a five-hour time change, it’s going to take about five days.”

You can, however, speed up the process by using or avoiding light. In other words, blocking light when you want to sleep and seeking it out when you want to be wide awake.

For many people, flying from east to west is less of a shock to the system than the other way round. Vikki explains that you can ‘phase delay’ your sleep in that direction in order to ease jetlag symptoms.

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“If you fly west, say to the US from the UK, you’ll want to shift your body clock later. The first night, you’re knackered, you go to bed, and then you wake up in the middle of the night and can’t go back to sleep, and then that has an impact on how you feel during the day.”

If you’re going on a longer break, it can be worth trying to adapt your sleep patterns before you fly. “If you’re flying west you want to delay your bedtime before you go,” says Vikki. “If you’re able to do this, then for the two or three days before you go, delay your sleep schedule by an hour a day, and use light in the evening to help yourself stay up, and then shift your sleep schedule.”

Conversely, if you’re flying east, shift your sleep schedule earlier and use bright light in the morning to force yourself to feel alert earlier.

Phoebe Smith practises 'extreme sleeping' in unlikely locations
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How to prevent jetlag when travelling

Seasoned travellers are familiar with jetlag and its effects, often coming up with their own ways of coping. Author, editor and extreme sleeper (and writer of the Calm app’s Sleep Stories) Phoebe Smith can often be found sleeping in the most unlikely places – under boulders or on clifftops and mountains – and is a frequent flier.

Phoebe finds that when she’s out on her travels she sleeps surprisingly well. “When I’m doing my extreme sleeping in very strange places – dangling off cliffs and such – I sleep without any kind of sleep aid,” she says.

“I think that’s because you’re so focused on staying safe that you’re not worrying about deadlines and other things that might be keeping you awake. You’re suddenly zoomed into the situation that you’re in. Often in those extreme environments it’s not a problem.”

In spite of her sleeping adventures, Phoebe has devised her own tips and tricks for a better night’s sleep when she’s travelling. “I always take a pillow from my bed with me when I travel,” she says. “I get some strange looks as people pull out their weirdly shaped travel pillows and I pull out my full-size pillow from the bed – but, to your brain, that pillow smells of your bed, which triggers something in your brain that goes ‘It’s bedtime’.”

When she’s in transit Phoebe sometimes tries to adapt to the time zone she’s travelling towards before she gets there, but if she’s there for a short time then she might stick to UK time.

“I went on a trip to Florida where they’re five hours behind, but I was only going to be there for four days, so I tried to stay on UK time,” she explains. “I was up at about 5am and going to sleep at about half past eight in the evening while I was away.

"And it works the other way, so if I’m going overseas and I know I’m going to be there a little bit longer, I’ll try to get in that time zone as I go over on the plane. I’ll change my watch and stop looking at what time I ‘should’ be on.”

Also, when you arrive, don’t work against your physiology by eating at the wrong time. That’s something Phoebe has become used to: “Don’t just accept the aeroplane food because it’s put in front of you. Get yourself on your destination time zone, and if it’s time to sleep, sleep – refuse the food.”

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How jetlag affects shift workers

While we usually associate jetlag with travellers, shift workers can also suffer many similar side effects – often more severely – such as fatigue, reduced concentration, dehydration, digestive problems, reduced performance, sleep issues and feeling as though they have a cold.

This is largely thanks to their limited exposure to blue light, which helps the brain to release the melatonin that regulates your sleep cycle. People who work night shifts for a long time frequently suffer from metabolism disruption that can result in diseases such as obesity and type II diabetes, as well as some cancers and cardiovascular disease. It can also cause some people to feel stressed or depressed.

“Because employees are often tired during night shifts, this can lead to risky situations due to reduced concentration,” says Toine Schoutens. Toine is the CEO of Propeaq, a company that makes glasses with built-in light to stave off jetlag and keep shift workers alert.

The blue light helps regulate melatonin production in the brain to control when you feel tired. The glasses include blue lenses for when you need to be alert and red lenses to block blue light for when you need to unwind and get ready for bed.

Toine’s first attempt to release a prototype of his glasses in 2007 was unsuccessful. But he was soon approached by the head coach of the Australian national swimming who was looking for an alternative to clumsy lightboxes that his team used to help keep themselves alert.

“Sitting in front of a lightbox every day is not an efficient use of your time,” explains Toine.

Since 2006, Toine has worked with the Dutch Olympic Swimming team to help their athletes perform at their best when they compete, helping them counteract the effects of international travel and early morning starts.

“Jetlag has a direct effect on the performance of athletes, frequent flyers and businessmen,” he says. “Their reaction rate and alertness decreases.”

Using the Propeaq glasses, it’s possible to shift your circadian rhythm by an hour to an hour and a half each day, allowing you to adjust to different time zones before you travel. And for shift workers looking to regulate their light intake, this bit of wearable tech can help to improve life at home and at work.

For a more low-tech solution to shift-disrupted sleep, Vikki suggests old-fashioned sunglasses to block out bright light on the way home from a night shift, and avoiding trying to cram in the day’s chores when you get home.

“Get into bed as quickly as possible after you finish your night shift and into a dark room,” she says. “If you imitate sleep quickly you’re much more likely to fall asleep, and then have a longer period of sleep.”

Young woman napping during flight
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5 ways to cope with jetlag


Synchronise your mealtimes

Try to get into the swing of your destination mealtimes as soon as you can, or you might wake up in the night feeling hungry or eat three dinners in one day. On the plane, don’t eat meals just because they’re being offered to you.


Use light to help you adapt

On a short trip, it’s not worth adapting to local time, so use light (daylight or artificial) to keep yourself awake and synchronised with your home clock. For longer trips, gradually adapt by an hour a day before you set off, using bright light to stay awake.


Stay hydrated

It’s a good idea to steer clear of caffeinated drinks. They might make you feel alert, but in the long run they’ll only disrupt your sleep patterns, making it harder for you to cope. Avoid alcohol on flights, too – it’s very dehydrating and can affect your sleep.


Block out noise and light

Try using an eye mask to block out unwanted light if you need to sleep on the plane or in daylight. They’re light and portable – ideal for hand luggage. Earplugs or noise-cancelling headphones are also handy.


Keep your bedtime routine

If you have a bedtime routine at home, stick to it as much as possible while you’re away or in transit. Change into your pyjamas, avoid screens, use aromatherapy products to help you relax, and listen to calming music or an audiobook.

This article was originally published in Sleep Well Magazine. Order your copy online here.