Jet Lag Survival Guide: Traveling 1-3 time zones westward


Jet Lag Survival Guide: Traveling 1-3 time zones westward

It’s so difficult to help your child adjust to a socially normal bed and wake 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 country with little drama. Note that travel can be complicated beyond jet lag. For more tips and tricks, check out our travel survival guide here.

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 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 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 your watch. In addition, during the biological night, there is a transition point where light the effect of light reverses. The figure below illustrates this change.

Chart showing sleep shifts following time zone changes.

This is 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.

Traveling 1-3 hours westward

First, ask yourself, do you have to shift your child? There are some situations in life where it may be possible to allow your child to remain on your old time zone. For example, if you are taking a trip that lasts less than a week or if you are only traveling one time zone, then it will be easier for your child if you just keep your watch set to your old time zone and put your child down at his biological bed/nap times.

The charts below show your child’s biological time and the relative clock time in a one-hour time zone change, a two-hour time zone change, and a three-hour time zone change. The most important thing to do when shifting your child’s sleep pattern is to ensure that you control his light exposure.

How to use these charts:

  1. 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.