Even the most thrilling international trip can be exhausting when you experience jet lag east vs west. You get to your destination and feel like you’re in the middle of the night. It can be difficult to fall asleep, get up too early, or feel tired throughout the day.
But why is it that sometimes it’s easier to go one way than the other?
The solution is in your body’s internal clock and how it reacts to time zone changes.
Knowing about jet lag east vs west can help you prepare for long-haul flights, adjust your sleep schedule, and recover more easily after landing. While both directions can throw off your body clock, it is usually more difficult for many travellers to fly east, as it forces the body clock to adjust earlier.
In this guide, we’ll delve into the science of eastbound and westbound jet lag, discuss the differences between the two, and provide some tips for adjusting to local time.
What Is Jet Lag and Why Does It Happen?
Jet lag is a temporary sleep disorder that can happen when you cross several time zones in a short period of time.
Your body runs on a natural 24-hour cycle known as the circadian rhythm. This internal clock helps to coordinate sleep and wakefulness, body temperature, hormone release and other biological functions.
One important component of this system is the suprachiasmatic nucleus (SCN), a small cluster of cells in the brain that regulates your body’s daily rhythms. Your internal clock relies on an important signal from light that helps keep it in sync with the outside world.
If you cross multiple time zones, the time will change instantly, but your internal clock will be closer to the time you left.
You may arrive in London from New York in the morning, when your body thinks it’s still night. Or you could come in from London in the afternoon when your body is already winding down for sleep.
This is because your internal clock is not in sync with the local time, which is what causes jet lag.
Common symptoms include:
- Difficulty falling asleep at your destination’s bedtime
- Waking up too early or repeatedly during the night
- Daytime tiredness and reduced energy
- Difficulty concentrating or remembering things
- Irritability and changes in mood
- Digestive discomfort or changes in appetite
The more time zones you cross, the more potential disruption. But your sleep patterns, travel plans, destination and personal circadian rhythm also play a role in how you feel.
Read the NHS guide to jet lag for more information.
Jet Lag East vs West: What’s the Difference?
The only difference between east and west is the direction of the adjustment of your internal clock.
When you fly east, you generally need to move your sleep and wake times earlier. This is known as a phase advance.
If you are flying west, you will typically want to adjust your sleep and wake times later. This is known as a phase delay.
Most people find it easier to delay their body clock than to advance it. This difference helps explain is jet lag worse flying east for many travellers.
Flying East: Why Is Flying East Usually Harder?
Flying east means travelling towards destinations where the local time is ahead of your departure location.
Imagine suppose you were to fly from New York to London. London is usually 5 hours ahead of New York, but at some points during the day light saving time change, the time difference is 4 hours.
Your body might still think it’s nighttime if you leave New York at night and arrive in London the next morning.
The key to adapting is to go to bed earlier and get up earlier based on the local clock.
The problem is that your internal clock might not be ready for sleep at the destination’s bedtime. You may find yourself lying awake at night, getting out of bed in the morning with difficulty, and feeling tired all day long.
Why is flying east worse for many travellers?
- Your day becomes shorter: You need to fit your sleep and waking hours into an earlier schedule.
- Your body clock must advance: Your internal rhythm needs to shift earlier than it naturally would.
- Sleep may be harder to initiate: You may not feel sleepy when local bedtime arrives.
- Early mornings become challenging: Your body may still be signalling that it is nighttime.
- Recovery can take longer: It may take several days to adjust after crossing multiple time zones.
This is a biological problem. In the absence of external time cues, the human circadian rhythm is slightly longer than 24 hours, but varies from person to person.
This is a natural phenomenon that is why it is easier to slow down the clock than to speed it up. The body needs to adjust its biological clock earlier when flying east and later when flying west.
But not all eastbound trips will be rough. It’s not just about the number of time zones crossed, but also the light exposure and your own sleep rhythm.
Flying West: Why Can It Feel Easier?
When flying west, you are heading towards a place where the time is earlier than where you are departing from.
For instance, when travelling from London to New York, you will usually find that the time is five hours earlier, but this can change depending on the season.
You may depart London in the morning and reach New York around midday. Your body may feel like it’s already late afternoon, making it easier to stay awake for a portion of the local day.
Jet lag westbound generally requires you to delay your internal clock. This translates to sleeping and waking up later than usual at home.
This is easier for many people to adjust to because the body may adjust better to a later schedule than an earlier one.
But westbound jet lag can still be a problem. During the transition period, you may feel sleepy earlier in the evening and wake up before sunrise.
The main point is that eastward travel tends to shift your body clock forward, and westward travel tends to shift your body clock back. Either way can interfere with sleep, but it’s easier to adjust when flying east.
Eastbound vs Westbound Jet Lag: A Quick Comparison
| Factor | Flying East | Flying West |
| Body-clock adjustment | Phase advance | Phase delay |
| Sleep schedule | Move bedtime and waking time earlier | Move bedtime and waking time later |
| Main challenge | Falling asleep early enough | Adjusting sleep to the new local schedule |
| Typical adjustment | Often more difficult | Often easier |
| Light strategy | Carefully timed morning light may help | Carefully timed afternoon or evening light may help |
| Preparation | Gradually shift your schedule earlier | Gradually shift your schedule later |
These are general patterns rather than guarantees. The most effective light-exposure strategy depends on your route, the number of time zones crossed, and your body’s current circadian phase.
How Long Does Jet Lag East vs West Last?
The recovery time for jet lag east vs west varies, but symptoms often improve over several days. Flying east can require a more challenging adjustment because your body needs to advance its internal clock, while flying west often allows a somewhat easier delay.
No single recovery rate is applicable to all. How quickly you adapt depends on the number of time zones crossed, when you are exposed to light, the quality of sleep, and personal factors.
For a more detailed explanation, read our related guide: How Long Does Jet Lag Last.
How to Reduce Jet Lag When Flying East
If your next trip takes you east, preparing before departure can make the transition easier.
1. Shift Your Sleep Schedule Earlier
Begin to change your sleep and wake schedule a few days prior to your trip.
For instance, you might consider adjusting your schedule 30 minutes earlier every day, as long as you still get the proper amount of sleep. It’s easier to make a gradual change than to go to bed several hours earlier all at once.
The aim is to start synchronising your body clock with the destination before you get there.
2. Get Morning Light at the Right Time
One of the most powerful cues for resetting your circadian rhythm is light.
If you are traveling east, getting the right amount of light at the right time at your destination can help advance your body clock. Limiting bright light in the late evening can also help with the adjustment.
However, timing matters. Light exposure at the wrong biological time can reset your clock in the opposite direction after crossing many time zones. If you have a large time zone difference, do not assume that the morning light is always the best option, use a route-specific light plan instead.
3. Follow the Destination’s Sleep Schedule
When planning to sleep or stay awake during your flight, take into account the local time at your destination.
Upon arrival, try to adhere to local eating and sleeping habits as closely as possible. You can use an eye mask, ear plugs and a travel pillow to get a good night’s sleep on the plane.
Don’t intentionally restrict sleep to make an adjustment. Rest is still a key factor.
4. Be Careful With Melatonin
Melatonin is a hormone that helps control the sleep-wake cycle. Some travellers find that melatonin supplements can help them cope with jet lag, but the effectiveness of these supplements is partly dependent on dosage and timing.
Melatonin may not be helpful if taken at the wrong time, and it can have side effects or interact with certain medications.
Talk to a pharmacist or health care provider before using it, especially if you are taking medication, have a medical condition, or are not sure when to use it.
5. Make Your First Day Manageable
Try to avoid early morning after arrival for demanding activities if possible.
Take advantage of daylight at the right times, eat at the right time, drink water regularly, and take time to get comfortable. A short nap can help if you are very sleepy, but long or late naps can make it harder to fall asleep at night.
How to Manage Jet Lag Westbound
When traveling west, it may take a little longer to adjust, but there are a few things that can help.
1. Move Your Sleep Schedule Later
In the days before departure, try going to bed and waking up slightly later than usual.
Even small adjustments can help prepare your body for a destination where local time is behind your home time. Avoid changing your schedule so dramatically that you become sleep-deprived before your flight.
2. Get Afternoon or Early-Evening Light When Appropriate
For many westbound journeys, appropriately timed afternoon or early-evening daylight can help delay the internal clock.
Light helps regulate melatonin production and signals to the brain when the biological day should begin or end. However, the ideal window depends on the time-zone shift and your internal clock.
For trips across many time zones, use a route-specific plan to avoid light exposure at a time that could shift your body clock in the wrong direction.
3. Stay Awake Until a Reasonable Local Bedtime
If you arrive during the day, try to remain gently active until the local evening, provided you can do so safely.
A walk outdoors, a light meal, or a relaxed activity may help you stay alert. If you are struggling with severe sleepiness, take a short rest rather than forcing yourself to stay awake at all costs.
Never drive when you are too tired to do so safely.
4. Avoid Falling Asleep Too Early
One common challenge with westbound jet lag is feeling sleepy well before the destination’s usual bedtime.
If you fall asleep in the early evening, you may wake up in the middle of the night or before sunrise.
Where practical, keep your evenings relaxed and use appropriately timed light to support a later schedule. Avoid excessive caffeine late in the day, as it can make it harder to sleep when bedtime arrives.
5. Keep Your Routine Consistent
Try to maintain a regular local bedtime and wake-up time after arrival.
Eat meals according to the destination’s schedule and avoid long daytime naps. Consistency helps reinforce the local routine while your internal clock catches up.
For additional guidance, visit the NHS jet lag advice page.
Does the Number of Time Zones Matter More Than Jet Lag Direction of Travel?
Direction is important, but it is only one part of the picture.
Crossing two time zones may cause little disruption for some travellers, while crossing eight or ten can make it much harder to maintain a normal sleep schedule.
Your experience can also depend on:
- Your chronotype: Whether you naturally prefer early mornings or later nights.
- Your flight schedule: Overnight flights and poorly timed sleep can add to fatigue.
- Your arrival time: Landing early in the morning can feel different from landing in the evening.
- Your sleep before travelling: Starting a journey already sleep-deprived can make symptoms harder to manage.
- Your individual response: People differ in how quickly their circadian rhythms adjust.
A return journey may feel very different from the outbound flight because the direction of travel changes. A trip that was manageable one way might be more difficult on the way back.
Common Mistakes That Can Make Jet Lag Worse
Understanding jet lag east vs west is only part of managing your symptoms. A few common habits can make adjusting to a new time zone more difficult.
Drinking too much alcohol: Alcohol can disrupt sleep quality, even if it initially makes you feel sleepy.
Overusing caffeine: Caffeine can temporarily improve alertness, but consuming it too late in the day may make nighttime sleep harder.
Taking long daytime naps: Long or late naps can reduce your ability to fall asleep at night.
Ignoring local time: Sleeping, eating, and planning every activity around your home time may prolong the adjustment.
Using sleep aids without guidance: Medicines and melatonin are not suitable for everyone, and timing can matter. Ask a healthcare professional or pharmacist for advice before using them.
For further practical advice, consult the NHS guide to jet lag.
Frequently Asked Questions
Is Jet Lag Worse Flying East or West?
Is jet lag worse flying east or west? The symptoms of jet lag vary from person to person, and are more likely to be a problem on eastward journeys. When you travel east, your body clock tends to speed up, and this can be more difficult than when you travel west. But the number of time zones crossed and individual differences also play a role.
Why Is Flying East Worse Than Flying West?
Why is flying east worse? When flying east, you typically end up sleeping and waking up earlier than usual, and your day is shorter. This change may not be what your internal clock is expecting, and you may find it hard to fall asleep at night and get up in the morning.
Can You Get Jet Lag When Flying Westbound?
Yes. Jet lag westbound can affect sleep, focus, energy and digestion. While many people adapt better to a later schedule, the time-zone difference and your personal sleep pattern still impact recovery.
How Many Days Does It Take to Recover From Jet Lag?
It may take several days and sometimes longer to recover from crossing many time zones. No single recovery rate exists as direction of travel, light exposure, sleep quality and individual circadian rhythms all affect adjustment.
Should You Sleep on the Plane to Prevent Jet Lag?
This will depend on your destination and flight schedule. If it’s nighttime at your destination, sleeping on the plane can help you keep up with the local time. If it is daytime, staying awake may help. The aim is to obtain sufficient sleep and to slowly synchronise your sleep with the local time.
Does Sunlight Help With Jet Lag?
Yes. Daylight is an important cue for the circadian rhythm. But its impact is dependent on the time of its receipt and the direction of travel. In suitable circumstances, morning light can help to advance the body clock, and later light can help to delay the body clock. The best time depends on the route.
Can You Prevent Jet Lag Completely?
It may not be possible to avoid it completely, especially after crossing numerous time zones. But, a gradual adjustment of the sleep schedule, light management, sufficient sleep and following local time upon arrival can help minimise its impact.
Final Thoughts: Direction Really Does Matter
Knowing what to expect when travelling jet lag east vs west can make a long flight more comfortable.
It is usually more difficult to fly east, as your body has to adapt to a different sleep pattern. The westbound flight is typically later, and that is often easier to work with. But both ways are not necessarily smooth sailing, particularly if you cross time zones.
The most effective way to do this is to plan ahead, get light at the right times, stick to a sleep schedule, and allow your body to adapt.
With a little planning, you can save some of your trip from being a time of exhaustion and more time enjoying your destination.
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From long-haul flights to coping with jet lag to tips on making international travel more comfortable, we want you to travel with more confidence.
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