Jet lag in children: traveling without throwing everything off

Shifting the schedule before you leave

Shifting bedtime by an hour a day for the two or three days before departure reduces the adjustment time once you land: later for a westbound flight, earlier for an eastbound one. The body doesn't adjust to a new time zone instantly, so it's best to start before boarding the plane.

This shift should stay gradual and modest: an hour a day is enough, there's no need to disrupt the whole week before departure. Arriving already synced to local time is rarely possible with school or naps structuring the week. The goal is simply to reduce the gap the body will have to make up once you're there.

For a very short stay of two or three days, the NHS suggests the opposite: keeping your usual meal and sleep times. That avoids resetting everything on the way out, then again on the way back.

How do you reset a child's body clock once you arrive?

Daylight is the most direct lever for resetting a child's internal clock: it's light that tells the brain whether it's day or night, far more than the time shown on a watch. Jet lag comes mainly from a body clock that is out of step with the new time zone (Waterhouse et al., The Lancet, 2007). Once you arrive, exposing the child to natural daylight during local daytime helps the body reset faster than staying shut in a hotel room with the curtains closed.

When the child gets that light matters too. According to the CDC, after an eastbound flight, bright light in the early morning helps move the clock earlier, while evening light is best avoided. After a westbound flight it's the reverse: bright light very early in the morning is best avoided, and late-day light helps push the clock later. The right timing depends on the direction of travel and the number of time zones crossed.

Staying awake during local daytime, even while tired from the flight, also helps the adjustment. The sleep pressure that builds up during waking hours makes it easier to fall asleep at the local bedtime that night. Conversely, a long nap in the middle of local daytime pushes back, by just as much, the moment the child will be ready to sleep that evening. The NHS likewise advises against daytime sleep; for a child who still needs a nap, it's better to keep it short and early in the local afternoon.

How long does jet lag last in a child?

Expect about an hour and a half of recovery per day heading west, and about an hour per day heading east. Jet lag, strictly speaking, applies to trips that cross at least two time zones; below that, the body absorbs the change without it really counting as jet lag. Beyond that threshold, how fast the body resyncs depends as much on the direction of travel as on the number of time zones crossed.

Heading west, the body adjusts at an average rate of about an hour and a half per day; heading east, it only recovers about an hour a day. A westbound flight effectively lengthens the day, which the internal clock accepts more easily. An eastbound flight shortens it, which requires the body to move its rhythm forward, a more demanding effort. In practical terms, six time zones eastward take longer to absorb than six time zones westward.

These averages give a rough order of magnitude. Six time zones westward (Paris to Montreal) mean about four days of resyncing. Six zones eastward (Montreal to Paris) take about six, and seven to eight zones eastward (Paris to Tokyo) about seven to eight. These are averages published for adult travelers, not promises: a child may be faster or slower.

An example: waking in the middle of the night after a westbound flight

After a westbound flight, a common scenario is a child who falls asleep easily but wakes in the middle of the local night, because their internal clock is still on home time. In Montreal, a child who usually gets up at 7 a.m. Paris time opens their eyes around 1 or 2 a.m. the first night. That wake-up then moves later by about an hour and a half a day on average.

If the child wakes like this, it's best to keep the room dark and the tone calm, avoid screens and games, and offer to lie back down with the stuffed animal or a quiet audio story. If they don't fall back asleep, let them rest without turning it into a small party. The aim isn't to get them back to sleep at all costs, but to avoid giving them a "daytime" cue in the middle of the night.

Eastbound, it's the reverse. Falling asleep is late, because the body isn't ready to sleep at local time, and the morning wake-up is hard. Morning light and a calm, screen-free evening (see screens before bedtime) help most.

Keeping a thread of the bedtime routine, even while traveling

The bedtime routine can travel with the child, even when the hotel room or the travel cot changes the setting. Keeping the same story, the same stuffed animal, the same sequence of steps before sleep lets the child hold on to something familiar, even when the time, the light, and the sounds around them have nothing familiar left.

In the first few days on site, it's better to accept a shifted bedtime or wake-up time than to force the child to hold out until the usual local hour no matter what. Resyncing happens gradually. Trying to speed it up through pressure only adds fatigue without shortening the timeline.

What the sources say, and when to talk to the pediatrician

The benchmarks in this guide come from recommendations written for travelers in general: the CDC and NHS pages on jet lag don't mention children. Applying them to a child is a reasonable extension, not pediatric proof.

Medication and melatonin are outside the scope of this guide. The NHS doesn't recommend melatonin for jet lag, and for a child the question is one for the pediatrician, before departure. It's also worth talking to them if the child has a known sleep disorder, takes medication or has a chronic illness, or if their sleep stays badly disrupted well past the estimated time.