Travel Survival Guide: Traveling 4-8 Time Zones Eastward

It’s a lot of work to guide a child to sleeping well at home, so the prospect of traveling across time zones with a baby or toddler can be daunting. We won’t say that adjustment to jet lag is easy, but your child’s circadian rhythm is designed to be flexible, and given time and careful control of light and darkness, your child can adjust to a trip across the globe with little drama. This blog covers how to handle eastward jet lag of approximately four to eight hours such as New York or LA to London or Paris or Hawaii to San Francisco or Chicago.

Most families will also travel in the other direction to come home, so check out this blog on traveling 4-8 time zones westward to complete your travel plan. If your travel involves jet lag of 1-3 hours, then check out our other blogs on eastward and westward jet lag.

The Science. A quick warning about this science section; it’s complicated. We’ve tried to simplify it, but if you find your head spinning don’t worry. Many university-level students of circadian biology have trouble with this topic in the beginning. You can just skip to the jet-lag plans below and follow them without knowing the science if needed!

Jet lag is so-called because with the invention of air travel humans became able to rapidly cross time zones faster than our internal body clock (or circadian rhythm) could keep up. The “lag” in jet lag refers to the time that it takes for your circadian rhythm to catch up to socially normal bed/wake/eating times in a new time zone.

The circadian rhythm is flexible and makes small adjustments every day even when you stay in the same time zone, because the circadian rhythm for about 70% of people is a little longer than 24 hours (about 30% have a circadian clock that runs a little shorter than 24 hours). This means that your child’s (and your) circadian rhythm has to make a small adjustment to the clock in order to keep biological time in synchrony with the 24-hour day. Think about it like this, your body clock is like a watch that runs about 12 minutes fast. Every morning when you wake up, you have to readjust your clock so that it keeps accurate time.

How does the circadian rhythm reset? It happens through the timing of your daily light exposure through your eyes (your eyes have to be open for it to work). If you weren’t exposed to light in the morning, then your biological bedtime and wake time would start to drift later and later every day. Babies are not born in sync with the 24-hour day and if you plot your baby’s sleep from birth you may see this type of shifting pattern, where the longest sleep bout doesn’t stay at night (more on newborn sleep here and in our 0-6 month class). Similarly, some people who are totally blind aren’t able to synchronize and develop a disorder called non-24 sleep-wake disorder, where the circadian rhythm just keeps following its own clock and cannot be reset to social time.

When you travel across time zones the same adjustment process will happen, BUT since the timing of light exposure (sunrise, sunset) relative to your child’s body clock will be off, the timing of light exposure could actually make things much worse. Why? Because light at different times of day does different things. Light in the morning shifts sleep earlier, while light in the evening shifts everything later, but of course “morning” and “evening” are relative to your child’s body clock, NOT local time. In addition, during the biological night, there is a transition point where the effect of light reverses. The figure below illustrates this change (note that this doesn't happen at exactly 3:00 am but it's around that time for most children).

This is why we cringe when parents tell us they turn on lights in the middle of the night! This is also why jet lag is hard. You have to think about what time it is in your child’s body and control light exposure relative to that time.

Finally, it’s important to know that the circadian rhythm is one of the two sleep drives (see basics on sleep here), but it also controls a great deal of other biological functions including hormone production, urine excretion, cognitive function and it also plays a role in meal timing. This means that when your child is jet-lagged, it’s not just sleep that will be off – everything will be off.

Why is eastward jet lag so hard?

Eastward jet lag can be straightforward, but some common situations complicate things when you travel eastward. This is best illustrated through example: imagine that your child sleeps from 7:00 pm to 6:00 am. If you are traveling westward, say from London to Boston, your child will need to be exposed to light in the evening, but you’ll need to keep it dark in the morning when you arrive in the US. This is fairly easy to do because the sun will be out later relative to your child’s internal clock and you’ll intuitively try to keep it dark and ask your child to sleep if she wakes at 1:00 am in Boston (6:00 am biological time; see our westward travel blog for more on this).

When you travel eastward, it’s a bit more complicated. Morning light exposure will help make the shift, but only if that morning light exposure is AFTER the transition point in your child’s body (see the graph above). For example, if you wake your child up for the day at 6:00 am London time, that’s 1:00 am biological time. Light exposure at that time could cause major trouble and shift your child’s drive to sleep in the wrong direction because your child's body will interpret light at that time as "evening."

Similarly, there is a strong drive to be awake right before your child’s biological bedtime, if you try to put your child down at 7:00 pm London time, that’s 2:00 pm Boston time, which will end up leading to your child taking a nap and then being wide awake for several hours after. As you’ll see below, it’s best to start close to your child’s biological bedtime/waketime in your new destination and work away from that – even if it’s a “socially unacceptable” bedtime or waketime.

How do you help your child adjust to travel 4-8 hours eastward (e.g. US to Europe)?

• Avoid the red-eye if you can. If you take a red-eye from the US to Europe, you’ll land at precisely the right time to shift in the wrong direction. This will start your child off with light exposure at the wrong time. The easiest adjustment will come with proper planning. If you can, avoid the red-eye and take a daytime flight.

• If you must take the red-eye. Do everything you can to keep your child shielded from the light during those early morning hours upon your arrival. Your child might wake up when you arrive and that is ok as long as you keep her shielded from the light. Some of our favorite tricks are bringing a carrier and nursing cover so that your baby can sleep on you but under the cover. You can also use a lightweight blanket or even baby/toddler sunglasses (seriously! We used them for our own kids and in addition to blocking out light they are super cute).

• Keep it dark in the morning until 3:00 am origin time at first. The reasons for this are complicated as described above, but think about the time it is in your child's body and keep it dark until at least 3:00 am relative to the time zone where you started. For example, when traveling from the US to Europe, you'll need to keep it dark until at least 8:00-9:00 am on the first few days. To do this, you might just throw a blanket over the existing curtains, bring along travel blackout shades, or cover the window with aluminum foil. Since you will be making these changes in an unfamiliar space, please use common sense and make sure your child is unable to reach the window cover to avoid the risk of entanglement or suffocation.

• Expose your child to bright light AFTER 3:00 am origin time. Morning light (meaning morning relative to your child's starting time zone) will shift your child's circadian rhythm earlier. Once it's 3:00 am or later in the time zone where you started, you'll need to expose your child to natural light to help your child's circadian rhythm adjust.

• Start with late bedtimes and shift earlier. Start by putting your child down very late to start and move a little earlier each day. For example, if you were traveling from Boston to London, and your baby normally slept 7:00 pm to 6:00 am in Boston, put your child down at midnight on your first day in London and keep it dark in the morning until at least ~8:00 am (3:00 am Boston time). Shift bedtime, wake time, and morning light exposure 15-30 minutes earlier each day until you reach your target schedule. Note that you will probably need to wake your child in the morning to make this happen.

• Adjust naps at the same pace as wake time. If your child normally wakes at 6:00 am and takes two naps spaced 2-3 hours apart, aim to put your child down following the same awake times you would at home. For example, if your child wakes at 11:00 am to start the day, the first nap would be around 1:30 pm and the second nap would be at about 5:30 pm. As you adjust wake time earlier, adjust naps earlier too. Don't worry that these naps are late, remember, you are starting with a later schedule on purpose to make it easier for your child to adjust.

• Pack smart! Review our travel survival guide for other suggestions about what to bring.

Determine your approach based on the length of your trip:

Consider a “compromise” sleep shift for short trips. There are some situations in life where it may be possible to partially shift your child in order to minimize the amount of disruption you will have during your trip and on the way back. For example, if you are taking a short trip to a relative’s house, then it will be easier for your child if you just keep your watch set to your old time zone and aim to have your child down a times near his biological bed/nap times, like letting him sleep from midnight to 11:00 am local time. This often works great if you are traveling to places like Italy or Greece because you can allow your child to stay awake and go out with you while you enjoy a late-night meal.

We've provided examples for babies and toddlers below. You can adjust these to your child's schedule to make a plan. If you aren't confident in making your own plan or if you have more complicated travel, book a consultation with us and we'll create a customized plan for you.

BABY EXAMPLE:

You are traveling from Boston to London and your eight-month-old normally sleeps from 7:00 pm to 6:00 am, with naps at 8:00 am and 12:30 pm.

Night 1. Put your baby down for the night starting around midnight, but wake him/her around 10:00 am (5:00 am in Boston). Expose your child to bright light as soon as possible to accelerate the sleep shift. This will result in an hour of sleep loss, so your child will be tired!

Day 1 Naps. Plan to put your baby down at noon for the first nap. It's ok if this nap is longer than normal but plan to wake your baby after 2-3 hours. Put your baby down for the second nap around 4:30 pm, limiting that nap to one hour (a longer/later nap will make it hard to shift bedtime earlier).

Night 2. Put your baby down for the night on the second night at 10:30 pm. It may be hard for your baby to fall asleep at this time because it is very early relative to home time. Keep your baby in the dark through any night waking. Wake your baby at 9:00 am and immediately open the curtains for morning light exposure.

Day 2 Naps. Put your baby down for the first nap around 11:00 am. Once again, it's ok if this nap is 2-3 hours. Put your baby down for the second nap 2-3 hours later, but make sure your baby is awake by 5:30 pm.

Night 3. Put your baby down at 9:30 pm. Keep it dark through any night waking. Wake your baby at 8:00 am and immediately open the curtains for morning light exposure.

Day 3 Naps. Put your baby down for the first nap at 10:00 am. It's ok if this nap is 2-3 hours. Put your baby down 2-3 hours later for nap 2, but make sure your baby is awake by 4:30 pm.

Night 4. Put your baby down for the night at 8:30 pm. Wake your baby at 7:00 am.

Day 4 Naps. Put your baby down for nap 1 at 9:00 am. It's still ok for this nap to last 2-3 hours. Put your baby down for the second nap 2-3 hours later, but make sure s/he is awake by 4:00 pm.

Night 5. Put your baby down for the night at 7:00 pm. Wake your baby at 6:00 am.

Day 5 Naps. Offer naps as normal at home, but continue to wake your baby in the late afternoon to protect bedtime.

It’s important to note that your child will probably not fully adjust in just five days. As a result, he may have some random waking at odd times. You do not need to try to force your child to sleep in these situations, just stay in the dark. If your baby is wide awake in the night, it is ok to play together as long as you keep the lights out. If you already have an established set of sleep cues that let your baby know that it’s time to sleep, then it is ok to use those cues to ask your baby to sleep (for example, rocking, bouncing, then putting down awake). In addition, this type of transition is more challenging making a gradual transition, because it is difficult to predict when your child will be ready for sleep. As a result, you must be sensitive to the fact that your baby or toddler may be accumulating a sleep debt. Use naps to help your baby make up for lost sleep rather than using an early bedtime, which could backfire.

TODDLER EXAMPLE:

You are traveling from San Francisco to London and your two-year-old normally sleeps from 7:00 pm to 6:00 am, with a single nap at 12:30.

Night 1. Put your child down for the night starting around 2:00 am (I know that sounds crazy, but that's 6:00 pm in San Francisco!). Wake your child around 12:00 pm (4:00 am in San Francisco). Expose your child to bright light as soon as possible to accelerate the adaptation. This will result in some sleep loss but that is a normal part of adjusting to a new time zone.

Day 1 Naps. Plan to put your child down at 4:30 for the nap, but wake your child by 6:30. If you have an older toddler (e.g., age 2.5 or older), it's ok to skip the nap if you think your child can handle it for one day.

Night 2. Put your child down for the night on the second night at midnight. Your child might have trouble falling asleep so be patient. Keep your child in the dark through the night. Wake your child at 11:00 am and immediately open the curtains for morning light exposure.

Day 2 Naps. Put your child down for a nap around 3:30 pm, but wake him/her by 5:30 pm. Once again, it's ok to skip the nap if you think your child can handle it.

Night 3. Put your child down at 10:00 pm. Keep it dark all night and through any night waking. Wake your child at 9:00 am and immediately open the curtains for morning light exposure.

Day 3 Naps. Put your child down for a nap at 2:30 pm and wake him/her by 4:30 pm.

Night 4. Put your child down for the night at 8:00 pm. Keep it dark through the night and any night waking. Wake your child at 7:00 am and immediately open the curtains for morning light exposure.

Day 4 Naps. Put your child down for a nap at 1:30 pm, but wake him/her by 3:30 pm.

Night 5. Put your child down for the night at 7:00 pm. Keep it dark during the night and through any night waking. Wake your child at 6:00 am and immediately open the curtains for morning light exposure.

Day 5 Naps. Nap your child at 12:30 as normal, but don't let the nap last more than two hours to protect bedtime.

It is important to note that your toddler will not fully adjust in five days (neither will you!). Your child may have some random waking due to overtiredness during this process. It is ok to go to your child to offer comfort (it can be stressful to sleep in a new place), but try to provide reassurance and then let your child fall asleep independently if that is what s/he is used to doing. For example, you might go to your child, sit for a few minutes stroking your child's hair, and then leave and say that you’ll be back in a minute. You'll then return to resettle your child and then leave again, continuing to go back and forth, providing reassurance in brief bouts until your child is asleep. That should allow you to provide comfort without creating new habits.

Need more help?

We are moms with formal education in sleep medicine, nursing, and behavior analysis. We always appreciate it when you share our blogs and resources with other parents who could benefit from the information. If you need a little help to figure naps out or if you are facing other challenges, then please check out our other blogs, our 0-6 month class, and sleep training class. We have blogs on schedules, travel, toddler issues, and more! If you just need to talk to someone who can help you devise a sleep plan, then feel free to book a one-on-one consultation with us. We are always happy to help!

References

Czeisler, C.A., Duffy, J.F., Shanahan, T.L., Brown, E.N., Mitchell, J.F., Rimmer, D.W., Ronda, J.M., Silva, E.J., Allan, J.S., Emens, J.S. and Dijk, D.J., 1999. Stability, precision, and near-24-hour period of the human circadian pacemaker. Science, 284(5423), pp.2177-2181.

Sack, R.L., 2010. Jet lag. New England Journal of Medicine, 362(5), pp.440-447.

Arendt, J., 2009. Managing jet lag: Some of the problems and possible new solutions. Sleep medicine reviews, 13(4), pp.249-256.

Roach, G.D. and Sargent, C., 2019. Interventions to minimize jet lag after westward and eastward flight. Frontiers in physiology, 10, p.927.