If you’re about to go on a long-distance flight, don’t worry about getting jetlag if you want to swiftly adapt to a new time zone, a new study suggests.
In a sample of 90 people, experts in Germany found a link between concerns pre-flight over developing jetlag, and severity of the disorder post-flight after landing.
They call this a form of the ‘nocebo’ effect – a negative version of a placebo, where people are more likely to experience an adverse effect if they expect or are worried about it occurring.
Amazingly, ‘classic’ factors thought to impact jetlag – the number of time zones crossed or travel direction – didn’t have an effect on jetlag severity, they found.
The study’s findings could be useful for travellers eager for a holiday this summer in a faraway country, once foreign holidays are permitted.
Severe jetlag can linger for days or even more than a week, hindering our ability to do our job. The new study suggests keeping a positive attitude pre-flight can limit its severity and duration (stock photo)
WHAT CAUSES JETLAG?
Jetlag happens when long haul travel disrupts your body clock – or circadian rhythm.
This internal cycle of bodily functions is synchronised to the 24-hour pattern of the Earth’s rotation.
So when people fly through different time zones, their senses are affected.
Waking in the night, tiredness, wonky hunger patterns and even digestive problems and severe headaches are all common complaints from jet lag sufferers.
The study was conducted by researchers at Ludwig Maximilian University of Munich and the German Aerospace Center, Cologne in Germany.
‘Jetlag disorder afflicts millions of travellers each year – a nuisance on holiday trips but also a danger in safety and performance-critical operations,’ the researchers say in their pre-print paper, yet to be peer-reviewed.
‘For effective prevention and treatment, it is critical to understand what influences jetlag severity.
‘These results suggest expectation as a relevant factor in jetlag experience – hinting at potential placebo effects and new treatment options.’
Jetlag is likely to cause fatigue, but it can also result in trouble thinking clearly and problems with the gastrointestinal tract.
Overall, it just makes it really hard to fall asleep at nighttime in your new time zone, or stay awake at work the day after landing.
It’s caused by disruptions to the innate biological clock in humans, called a circadian rhythm, which regulates when we become sleepy and when we’re more alert.
THE FOODS TO EAT WHEN JET LAGGED
Registered nutritionist Lily Soutter recommends the following foods to overcome jet lag:
- Cherry juice – contains melatonin, which influences our body clock to aid sleep.
- Kiwis – are high in the ‘happy hormone’ serotonin, which converts to melatonin in the body.
- Eggs – are a rich source of vitamin B12, which regulates melatonin signalling in the brain and can induce alertness.
- Green leafy vegetables – contain calming magnesium, which also regulates our sleep-wake cycle.
- Whole grains – stimulate the release insulin, which manages our blood sugar levels and therefore our alertness.
- Chamomile tea – is a very calming drink that has been shown to reduce insomnia.
Travel across time zones, especially long-distance travel, means the body clock has to reset itself.
Light is that clock’s strongest regulator, meaning one of the best therapies to beat jetlag is taking a walk in the sunshine rather than succumbing the temptation to sleep during the day.
‘After a flight across multiple time zones, most people show a transient state of circadian misalignment causing temporary malaise known as jetlag disorder,’ the experts say.
‘The severity of the elicited symptoms is postulated to depend mostly on circadian factors such as the number of time zones crossed and the direction of travel.’
For their study, researchers examined the influence of expectations prior to flight, compared to these ‘classic’ factors, on jetlag severity.
The team monitored jetlag symptoms in 90 individuals between the age of 18 and 37 – all of whom were inexperienced with air travel.
The participants completed questionnaires twice daily for one week before and after flights crossing more than three time zones.
Pre-flight questions included things like whether they expected to get jetlag and how severe they expected it to be.
On average, jetlag lasted for about four days, but it was less common than the participants thought it would be, the researchers found.
More than 75 per cent of the participants said they expected to get jet lag, but only 54 per cent did.
The only factor that did have an effect on jetlag was expectation of how severe it would be prior to travel, although the team admitted it the effect was only small.
The classic factors showed ‘little to no link with jetlag symptom intensity and duration’.
Getting sunlight during the day in your new time zone is known as one of the best ways to knock jetlag on the head (stock image)
Researchers believe there are individual differences that influence how much certain factors affect different travellers.
‘People are so variable,’ study author Eva C Winnebeck Winnebeck at Ludwig Maximilian University of Munich told New Scientist.
‘Length of travel could affect someone really badly, but have no effect on someone else.’
The study’s findings back up advice from Laurie Berryman, aviation and former Emirates vice president for the UK.
‘Maintaining a positive attitude generally can help avoid stress and aid rest,’ he previously told MailOnline.
‘Talking to your in-flight neighbours can help you feel more comfortable throughout the journey, helping you to relax, sit and sleep better.’
TIPS TO PREVENT AND TREAT JETLAG
Specialist sleep researcher Dr Yu Sun Bin from the University of Sydney says long-haul travellers can reduce their alcohol intake to help avoid severe jetlag (stock image)
TAKE A WALK
Going for a walk in the sunshine is better than taking a nap to combat jet lag, airline research in 2019 found.
Qantas and University of Sydney fatigue specialists from the Charles Perkins Centre released their findings into how passengers cope with long, overseas flights.
Specialist sleep researcher Dr Yu Sun Bin, from the university team, said less than half of Qantas passengers surveyed took a walk outside after arriving at their destination.
‘We know that going outdoors for sunlight at the destination is one of the most important strategies for syncing the body clock, but only 47 per cent of passengers made the effort to do it,’ she said.
Sleep experts recommend walking outside after a long flight so a traveller can adjust to a new time zone.
Dr Sun Bin also recommended that passengers cut back on the amount of beer and wine they consume on a long flight.
‘Drinking more than a few glasses of alcohol will make jet lag worse,’ she said.
‘It might make us fall asleep faster but beyond a certain point, it also disrupts the quality of sleep and causes dehydration.’
The NHS says: ‘Do not drink too much caffeine or alcohol – they can make jet lag worse.’
Lemons have properties that will help to fight off dehydration, bananas are rich in potassium and magnesium, which act as natural muscle relaxants, and cherries a natural food source of melatonin, a hormone that helps to reset the body’s clock.
Goji berries can enhance sleep quality and fresh ginger is another source of melatonin, according to luxury hotel chain Swissotel.
If jet lag has affected your digestive problems, munching on super grain, quinoa, can offer some relief.
…BUT DOES MELATONIN WORK?
Melatonin is a natural hormone released by the body in the evening to let your brain know it’s time to sleep – and it comes in tablet form as a method to reduce jetlag.
According to the Mayo Clinic, melatonin aids sleep during times when you wouldn’t normally be resting, making it beneficial for people with jet lag.
‘As a jet lag remedy and sleep aid, melatonin has been widely studied, and it’s now a commonly accepted part of effective jet lag treatment,’ Mayo Clinic says.
‘Your body treats melatonin as a darkness signal, so melatonin generally has the opposite effect of bright light.’
However, the NHS says melatonin tablets are not recommended for jet lag because there’s not enough evidence to show they work.
NHS tips to prevent jetlag are drinking plenty of water, keeping active by stretching and regularly walking around the cabin and trying to sleep if it’s night time at your destination.
When arrived at your location, the NHS also advises changing your sleep schedule to the new time zone as quickly as possible, setting an alarm to avoid oversleeping in the morning and going outside during the day to soak up the natural light.