Disclaimer: This article is for informational purposes only and isn’t intended to diagnose, treat, or replace professional medical advice. If your child experiences persistent snoring or symptoms of sleep apnoea, please speak to a qualified healthcare professional.
Whether you’re travelling for business, heading off on holiday or returning home after a long-haul flight, the effects of jet lagcan quickly take the shine off your trip. You might find yourself wide awake at 3am, struggling to stay awake during the day, or feeling completely out of sync with your surroundings.1
While you can’t always avoid jet lag, understanding what causes it, recognising the symptoms and making a few simple adjustments before, during and after your journey can help your body adapt more quickly.
What is jet lag?
Your body runs on an internal 24-hour cycle, known as your circadian rhythm. This controls much more than when you feel sleepy, it also influences your energy levels, hormone production, digestion and body temperature.2
When you travel across several time zones, your body doesn’t immediately adjust to the new local time. Instead, it continues following your usual sleep and wake routine from home. This mismatch between your body clock and the time at your destination is known as jet lag, and the effects of jet lag can leave you struggling to sleep at night or feeling unusually tired during the day.
What causes jet lag?
Jet lag will often affect you when you travel across three or more time zones and your body hasn’t yet adjusted to the new local time.3 When you suddenly arrive somewhere several hours ahead or behind your usual routine, your body continues operating on “home time”. Until your internal clock adjusts, you may struggle to sleep at night or feel alert during the day. This mismatch between your body’s natural daily rhythms and the local time is what causes the effects of jet lag.
However, the journey itself can also contribute to the jet lag. Long flights often involve disrupted sleep, dehydration, sitting for long periods and changes to your usual eating routine. If you’ve had a stressful journey or were already sleep deprived before travelling and are in ‘sleep debt’ this may make the symptoms of jet lag, feel even more noticeable.4
What are the symptoms of jet lag?
Difficulty sleeping Perhaps the most frustrating symptom is finding it difficult to fall asleep when it’s bedtime at your destination. Some people also wake much earlier than expected or find their sleep is lighter and more broken than usual.
Feeling tired during the day Even after what feels like a full night’s sleep, you may still feel exhausted, struggle to concentrate or find it harder to stay awake during meetings, sightseeing or travelling.
Changes in mood Poor sleep can affect how you feel emotionally too. It’s common to feel irritable, less patient or simply not quite yourself while your body clock adjusts.
Digestive changes Your digestive system also follows your body’s natural rhythm. This means some people experience changes in appetite, bloating, constipation or an upset stomach during the first few days after travelling.
East vs. west travel
If you’ve ever wondered why some trips seem harder to recover from the effects of jet lag than others, the direction you travel could be the reason.
Travelling east is generally considered more difficult because it requires your body to fall asleep earlier than it’s used to, which can make it harder for your internal body clock to adjust. Travelling west usually means staying awake for a little longer, which many people’s body clocks find easier to adapt to.6
For example, travelling east from London to Tokyo involves moving several hours ahead of your usual time zone, meaning your body needs to adjust to an earlier sleep and wake schedule. In contrast, travelling west from London to New York requires your body clock to shift later, which is generally considered easier for most people to adapt to.
The Jet-Lag Severity Index ranks common travel routes based on factors including the number of time zones crossed, direction of travel, hemisphere changes and the impact on the body’s circadian rhythm. Its findings highlight how some journeys may be more challenging to recover from than others, depending on the route taken7.
Jet lag duration: How long can symptoms last?
Many travellers wonder how long will jet lag last? Typically, jet lag symptoms begin to improve within a few days as the body gradually adapts to the new time zone. Exactly how long jet lag symptoms last depends on several factors, including how many time zones you’ve crossed, the direction you’ve travelled and your usual sleep habits.
Generally, your body clock adjusts to a new time zone at a rate of around 60 – 90 minutes per day. This means that when crossing several time zones, it can take your body several days to fully adapt.8
Reducing jet lag before and during travel
Although you can’t completely avoid jet lag, a little preparation can make the adjustment easier. If possible, try shifting your bedtime and wake time closer to your destination’s time zone a few days before you leave. When travelling east, going to bed and waking the next day slightly earlier can help your body prepare for the earlier schedule. If you’re travelling west, staying up slightly later may make the adjustment easier.9
The choices you make during your flight can also have a surprising impact on your jet lag recovery. Try to stay hydrated by drinking plenty of water, and limit alcohol and caffeine, particularly if you hope to sleep on the plane. If it’s nighttime at your destination, try sleeping during the flight, and consider using travel sleep essentials such as an eye mask, earplugs or a supportive travel pillow to make resting easier.
Getting up to stretch your legs every couple of hours can also help you feel more comfortable after a long journey.10
Managing jet lag once you’ve arrived
A key step to managing jet lag once you’ve reached your destination is helping your body adjust to its new schedule as quickly as possible.
One of the most effective ways to reset your internal body clock is through natural daylight. Spending time outside during the day helps signal to your brain that it’s time to be awake, making it easier for your body to adapt to the new routine.
It can also help to follow the local schedule as soon as possible. Try eating meals at your destination’s usual times and avoid the temptation to sleep for long periods during the day. If you need a nap, keeping it short (around 20 to 30 minutes) can help you recharge without making it harder to sleep at night and try to take it closer to when you land rather than later on during the day as this helps to avoid trouble sleeping later on at night.
Prioritise good sleep habits while your body adjusts. Creating a comfortable sleep environment, keeping your bedroom cool, dark and quiet, limiting screen time before bed, and avoiding caffeine and alcohol close to bedtime can all support better quality sleep and help you get back into your routine faster.11
Can melatonin help with jet lag?
Many travellers consider melatonin to help with jet lag, as it is a hormone naturally produced by the body to signal that it’s time to sleep and to help regulate your sleep-wake cycle.
Research suggests that melatonin may help reduce the severity of jet lag symptoms and support a quicker adjustment to a new time zone when taken at the right time. For some people, it may help the body clock adapt faster after long-distance travel.12
If melatonin is recommended, it is typically taken at your normal bedtime once you arrive at your destination (but not before 8pm or after 4am) and can be used for up to five nights in a row.
Melatonin is not suitable for everyone and may not be available on NHS prescription in all cases. If you are considering using melatonin for jet lag, it is best to speak with your GP or healthcare professional for advice.13
Final thoughts
Jet lag is a common challenge for many travellers, but it doesn’t have to put a pause on your plans or affect your trip.
By understanding what causes jet lag and taking simple steps to support your body’s natural sleep-wake cycle, you can help your body adjust more smoothly to a new time zone. Staying hydrated, getting natural daylight, maintaining healthy sleep habits and creating a consistent routine can all support recovery, helping you feel more refreshed and ready to enjoy your journey sooner.
Dr. Maja Schaedel, Sleep Expert & Clinical Psychologist, Director of The Good Sleep Clinic
Learn more about sleep or take our interactive snoring test
Eastman, I. and Burgess, H.J. (2009) ‘How To Travel the World Without Jet lag’, Sleep Medicine Clinics, 4(2), pp. 241–255. Available at: https://pubmed.ncbi.nlm.nih.gov/28719491/
Burgess, H.J., Crowley, S.J., Gazda, C.J., Fogg, L.F. and Eastman, C.I. (2003) ‘Preflight adjustment to eastward travel: 3 days of advancing sleep with and without morning bright light’, Journal of Biological Rhythms, 18(4), 318–328. doi: 10.1177/0748730403253585. Available at: https://pubmed.ncbi.nlm.nih.gov/12932084/
Costello, B. et al. (2022) ‘The effectiveness of melatonin for the prevention and treatment of jet lag: A systematic review and meta-analysis’, Sleep Medicine Reviews. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC8958662/
