It’s so difficult to help your baby adjust to “socially normal” bedtimes and waketimes 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. 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 the 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 synch 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. 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 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 your watch. In addition, during the biological night there is a transition point where the effect of light reverses. The figure below illustrates this change.
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 function 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 straight forward, but there are some common situations that 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).
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. Similarly, there is a strong drive to be awake right before your child’s biological bedtime, if you try to put him down at 7:00 PM London time, that’s 2:00 PM Boston time, which will basically 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.
Traveling Eastward Four to Eight Hours (e.g. US to Europe)
Avoid the red-eye. If you take a red-eye from the US to Europe, then you’ll land at precisely the right time to shift in the wrong direction. This is obviously a problem, because it 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. If you have to take the red-eye, then do everything you can to keep your baby shielded from the light during those early morning hours upon your arrival. She might wake up 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 high quality sunglasses (seriously! We used them for our own kids and in addition to blocking out light they are super cute).
Prepare your child’s sleep environment. Even if you don’t take the red-eye your child could end up having an early waking on subsequent mornings if you don’t have curtains sufficient to black out the windows in the morning. Make a plan to black out those windows. You might just throw a blanket over the existing curtains, bring along redi-shades (our favorite black out shades), or pack a contractor bag and painter’s tape to black out windows. If you use the contractor bag method, then obviously please use common sense and make sure your child is unable to reach the bag to avoid a potential suffocation risk.
Load your phone with a white noise app to block out noises when the rest of the world is awake and making noise.
Bring familiar objects from home, a sleep sack/swaddle/blanket and/or lovey depending on your child’s age.
Consider a “compromise” sleep shift. 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.
Make a plan. The most important thing to do when shifting your child’s sleep pattern is to ensure that you control her light and dark exposure relative to what is happening in her body. Every day your child’s biological bed/wake time will shift if you carefully control his exposure to light and darkness.
Gradual transition. If you are moving permanently to the new time zone or spending a long time there, then the best thing to do is to make the gradual shift, preserving your baby or toddler’s bed/wake/nap times and moving all sleep 15-60 minutes earlier each day. This means that you would start by putting your baby down at bedtime very late to start and move a little earlier each day. For example, if you were moving from Boston to London, and your baby normally slept 7:00 PM to 6:00 AM in Boston with two naps at 8:00 AM and 12:30 PM, then you would put him down at midnight on your first day in London and keep it dark in the morning until ~11:00 AM (6:00 AM Boston time). For naps you would put your baby down at 1:00 PM and 5:30 PM to start. Every day you would move your baby’s bed/nap times 15-20 minutes earlier until you reached your target bed/nap times. The most important thing that you need to do when making a gradual transition is to wake your baby 15-20 minutes earlier each day. When making a gradual transition with a toddler, you would need to do the same thing, but you would be able to put your toddler down up to an hour earlier each day.
Rapid Transition. It would take over two weeks to gradually shift a child from San Francisco time to London time. This is impractical for most families who travel for short periods of time to visit family. In situations like this you can get away with sacrificing some of your child’s sleep for a more rapid transition. The key is to control your child’s exposure to light and darkness in a way that will promote adjustment and to use a little bit of strategic sleep scheduling to ensure your baby is ready for sleep when you are asking him to sleep. Use the chart below to identify when your child needs to be kept in the dark and you’re your child should be exposed to bright light.
Key elements in planning your rapid adjustment strategy:
Make sure that you keep it dark during the vulnerable period indicated on the chart.
Make sure you keep it bright during times when light will have its strongest effect. These windows of darkness and light will shift a bit each day, so it is important to make sure that you expose him to light about an hour earlier each morning, even if that means that you need to wake him up.
If you have a baby, then allow your child to make up for lost sleep during the first half of the day and wake your child from long/late afternoon naps in order to protect bedtime.
If you have a toddler, then strategic nap skipping will accelerate your child’s adjustment. Try to avoid consecutive days of nap skipping in order to avoid having your child become too overtired.
You may be able to do an earlier bedtime on a night following poor or nonexistent napping, but on the following day your child may not be able to fall asleep at the same time due to having a lower sleep pressure.
You don’t need to worry too much about when your child actually sleeps, you just need to make sure that you are controlling his exposure to light and darkness.
The examples below illustrate how this might unfold for a baby and a toddler:
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 and 12:30
Night 1. Put your baby down for the night starting around 12:00 AM, but wake him around 10:00 AM (5:00 AM in Boston). Expose him to bright light as soon as possible in order to accelerate his sleep shift. By waking him an hour early, you are essentially depriving him of an hour of sleep.
Day 1 Naps. Plan to put him down at 12:00 for his first nap, but let him take a nice long nap if he has accumulated a sleep debt. Plan to put him down for his second nap around 4:30 PM, but wake him if he is still asleep at 5:30 PM.
Night 2. Put him down for the night on the second night at 10:30 PM. Although this is in the middle of the strong drive to be awake, it is likely that the sleep loss that your baby accrued from the prior night will allow him to fall asleep a bit earlier. Wake your baby at 9:00 AM and immediately expose him to light.
Day 2 Naps. Put your baby down for naps around 11:00 AM and let him sleep as long as he wants to sleep. It is ok for him to make up for some of the lost daytime sleep. Put him down for his second nap 2-3 hours later, but make sure he is awake by 5:30 PM. Put him down for the night at 9:30 PM.
Night 3. Put your baby down at 9:30 PM. Wake him at 8:00 AM and immediately expose him to light.
Day 3 Naps. Put your baby down for nap 1 at 10:00 AM and let him sleep as long as he wants. Put him down 2-3 hours later for nap 2, but make sure he is awake by 4:30 PM.
Night 4. Put him down for the night at 8:30 PM. Wake him at 7:00 AM.
Day 4 Naps. Put your baby down for nap 1 at 9:00 AM and let him sleep as long as he wants. Put him down for the second nap 2-3 hours later, but make sure he is awake by 4:00.
Night 5. Put your baby down for the night at 7:00 PM. Wake him at 6:00 AM.
Day 5 Naps. Nap your baby as normal at home, but continue to wake him 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 if he is unable to sleep. If your child is awake when it is important that he stay in the dark, then it is ok to let him play 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 than the 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. In these cases your child may fall asleep earlier than described in the example and sleep well one night. Unfortunately once your child catches up on sleep, then it will probably be very difficult for him to fall asleep on subsequent nights due to the wake maintenance zone.
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 child baby down for the night starting around 2:00 AM (6:00 PM in San Francisco), but wake him around 12:00 PM (4:00 AM in San Francisco). Expose him to bright light as soon as possible in order to accelerate his sleep shift. By waking him an hour early, you are essentially depriving him of an hour of sleep.
Day 1 Naps. Plan to put him down at 4:30 for his nap, but wake him by 6:30 OR consider skipping his nap if he can handle it for one day.
Night 2. Put him down for the night on the second night at 12:00 AM. Although this is in the middle of the strong drive to be awake, it is likely that the sleep loss that your child accrued from the prior night and will allow him to fall asleep a bit earlier. Wake your child at 11:00 AM and immediately expose him to light.
Day 2 Naps. Put your child down for his nap around 3:30 PM, but wake him by 5:30. Consider skipping the nap if he can handle it, but don’t skip a nap two days in a row in order to avoid having him accumulate too much sleep debt.
Night 3. Put your baby down at 10:00 PM. Wake him at 9:00 AM and immediately expose him to light.
Day 3 Naps. Put your child down for his nap at 2:30 PM, but wake him by 4:30 PM. Consider skipping the nap if he can handle it, but don’t skip a nap two days in a row in order to avoid having him accumulate too much sleep debt.
Night 4. Put him down for the night at 8:00 PM. Wake him at 7:00 AM.
Day 4 Naps. Put your child down for his nap at 1:30, but wake him by 3:30.
Night 5. Put your child down for the night at 7:00 PM. Wake him at 6:00 AM.
Day 5 Naps. Nap your child at 12:30 as normal, but continue to wake him in the late afternoon 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 (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 he is used to doing. For example, you might go to him, sit with him for a few minutes stroking his hair and then tell him you’ll be back to check on him, then leave and come back a few minutes later. Keep going back and forth, providing reassurance in brief bouts until he is asleep. That way you will not create a new sleep association that will cause him to get up every night seeking comfort.
How to use these charts:
Print the blank chart (at the bottom of this blog) and shade in your child’s normal sleep timing in the line under your home time zone.
Shade in the “dark” time starting with the range of time from 11:00 PM to 4:00 AM in your child’s body.
When you arrive at your destination, put your child down relative to the new time and adjust based on your schedule.
If you need your child to adjust right away, begin shifting your child before your trip.