And when she does wake up at 4 a.m.—because let’s face it, she will, as I’ve found that no matter when I put my son to bed, he wakes up at the same time—go over to her with the lights still out and explain that it’s still nighttime and she needs to go back to sleep. It may help, Waldburger says, to bring along one of those sleep-training clocks that signals whether it’s time to get up or not; it can be better for bad news to come from an electronic device than from a parent. Look, honey, the situation is out of my hands. (I placed my Amazon order this morning.)
If that fails, and your kid refuses to entertain herself with the backpack full of crap you’ve packed for just this situation, well, you may have to get up. But keep her playing in a semi-dark room until a reasonable wake-up time, because low light helps to train her brain that it’s still nighttime and that dammit, she should still be snoozing—hopefully, she will then sleep in later tomorrow. (So, note to self: This year, don’t turn on every single living room light at 4 a.m.)
Indeed, when it comes to retraining your kid’s internal clock, light is your best friend, because it is an essential cue for regulating circadian rhythm. When it’s nighttime in your new time zone, keep the lights low inside. When it’s daytime in your new locale, expose her to bright light—ideally, natural outdoor light. One study found that when you’re traveling east-to-west, the best time to expose yourself and your kids to light is between the hours of 2 and 3 p.m., because this tells the brain it’s still light out at a time when, in the old time zone, it would be getting dark. If you’re traveling west-to-east, on the other hand, you should expose you and your kids to natural light between the hours of 6 and 8 a.m. In general, make your kid’s indoor light environment emulate what’s outside as much as possible, and get outside as much as you can, too.
So let’s say you’ve gone east-to-west and your kid has woken up at 4 a.m. You know she’s going to be ready for her first nap way earlier than she otherwise would be. What do you do? Not what I did, which was to put my son in bed as soon as I saw him yawn. (Hey, I wanted a nap too.) Instead, try to keep her awake longer, Waldburger says. If your kid normally wakes up at 6 a.m. and takes a 9 a.m. nap, then when she wakes up at 4 a.m., try to stretch her nap toward 9 a.m. anyway—even though, yes, she’s going to be a holy terror starting at 7. And let her (and you) have a good nap, Weissbluth says—the cutting-naps-short advice applies mostly to west-to-east trips when you run the risk that a nap could cut to close to the new bedtime.
What if you’re crossing far more than three time zones? Wardburger suggests flying at night, because kids sleep better on night flights, helping to start the vacation off on a more well-rested note. Again, try to manipulate naps so that your kid isn’t taking a nap close to her expected new bedtime; expose her to natural light cues and switch over all of her meals to the new time as quickly as possible.
There’s one other controversial idea that’s worth bringing up, and that is the notion that you should start shifting your child’s schedule over to the new time zone a few days before you travel. In theory, this approach makes sense—if you can push your kid’s bedtime ahead or back by an hour before you go, it’ll take less time for her to acclimate to the new time zone. But Weissbluth warns that while this approach might work for adults, with kids it can backfire. “I don’t think any parent can really do it,” he says, because you need switch over all of their social cues, too. You need to move lunch an hour earlier, nap an hour earlier, dinner an hour earlier. If your kids are at home all day with you, this feat might be possible, but if they are in school or daycare, you are probably out of luck. Ultimately, Weissbluth says, many parents who try to move their kids over to a new time zone in advance end up traveling with tired kids, which can make sleep issues worse on vacation—not better.
The bottom line is this: Unless you have gone east with kids you want to hang out with until late night, switch everything over to the new time once you arrive—mealtimes, naptimes, bedtimes. Expose your kids (and yourself!) to natural light when it’s light out and darkness when it’s dark out. And don’t be afraid to break a few rules. You usually sing one song before bed but she’s asking for two? Sing two. Traveling is tough on everybody, but it’s far harder on a young kid, as she’s been torn, often unwillingly, from her familiar surroundings to go somewhere that smells and looks weird, gets dark and light at strange times and is full of people she doesn’t really know. Remind yourself of this the fifth time your beautiful child wakes up in the middle of the night screaming: She’s probably more scared than you are exhausted.
Update, Dec. 18, 2013: This post has been updated to clarify that parents traveling from the East Coast to the West Coast should try stretching the nap as close to 9 a.m. as possible, but that making it to 9 is unlikely.