Most Jet Lag Advice Doesn't Work: Here's Why + What To Do On Your Next Flight
Nothing derails a trip like jet lag—especially if you have limited time in your destination or need to be on your game upon landing. So is there any way we can skip over the travel woe? Yes and no. According to circadian rhythm specialists, jet lag is more nuanced than we give it credit for. This means that cut-and-dried advice on how to treat it doesn't always work—and could actually make it worse.
Here's why jet lag really happens, who it tends to hit the hardest, and how to minimize its impact trip by trip.
What is jet lag?
"Jet lag is the delay between your internal clock and your new time zone," Jamie Zeitzer, Ph.D., an associate professor of sleep medicine at Stanford University, tells mbg.
It occurs when we change time zones too quickly for our internal clocks to catch up to our new surroundings. If, for example, you fly from Los Angeles to New York City in one day, come 11 p.m. at your destination, your body will still feel like it's 8 p.m.
This mismatch can cause fatigue, difficulty sleeping at the appropriate times, and a number of other side effects.
Why jet lag happens.
Everyone has a circadian rhythm, or internal clock, housed in the hypothalamus regions of their brains. This is one of the many clocks "ticking" in our bodies at all times—but it's far and away the most important.
Not only does the circadian clock dictate when we feel tired and awake, but it also plays a role in keeping other processes in the body—from digestion to hormonal release—on schedule (hence the nickname "master clock").
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Our circadian clocks run on a roughly 24-hour loop (though they all differ slightly, which we'll get into later). This loop is primarily influenced by light. We function best when we minimize disruption to this loop as much as possible by going to bed and waking up around the same time, taking in sunlight during the day and darkness at night, etc.
Even though light shifts throughout the year as the days get longer and shorter, these changes happen gradually enough that our clocks can easily adjust. When we take a flight halfway around the world in one day, though? That's bound to throw the clock, and everything it oversees, out of whack.
"When you travel across time zones rapidly, you change the light-dark cycle so quickly that the body clock can't keep up," explains Steven Lockley, Ph.D., a neuroscientist and the co-founder and chief scientist at Timeshifter. There's a reason that we don't get "ship lag," he adds, since traveling via slower modes of transportation gives our clocks adequate time to adjust to changes in the light-dark cycle.
"Never in nature would you have experienced a change in the light-dark cycle of, say, seven hours in a day... It's completely unnatural, and your brain doesn't know how to cope with it as it thinks you are waking and sleeping at the wrong time," Lockley says. "So what it does is it has to reset itself—but it can't reset itself seven hours in one day."
Until our clocks fully reset to our new time, we won't feel our best in our new environment.
Common symptoms of jet lag.
The most obvious symptom of jet lag is a disrupted sleep schedule. Depending on who you are and where you're traveling, you might find it difficult to fall asleep at night, wake up in the morning, and/or stay awake in the middle of the day. Due to the other body processes that fall under the circadian rhythm's domain, you may also experience:
- Indigestion and upset stomach
- Cognitive fatigue and fogginess
- Reduced ability to fight infection
- Impaired athletic performance
Continual lack of sleep at your destination can exacerbate many of these symptoms. Zeitzer notes that many of the side effects of a long plane flight—such as dehydration, stress, and stiffness—can also add to the discomfort of jet lag.
How long does it typically last?
Jet lag ends once your internal clock has fully synced up to the light in your new area. As a general rule of thumb, the circadian rhythm can naturally shift around one hour every day. So if you don't do anything else to reset your internal clock, it will take about a week to fully adjust to a seven-hour time difference.
However, Lockley adds, some of us will be able to adjust faster due to our sleep chronotype. As mentioned earlier, the timing of our personal clocks differs slightly. Instead of a precise 24-hour loop, some may run on a 23.5-hour cycle, others a 25-hour cycle. Those who have a shorter clock tend to be morning people, while those who have a longer type are more night owls.
"Most people find it easier to travel west," Lockley explains, "and that's because three-quarters of people have an internal circadian clock longer than 24 hours, which is the equivalent of going west a little bit each day." Since you're traveling in the direction that your clock naturally wants to go, you may find it easier to overcome jet lag upon landing. (Of course, you'll have the opposite experience after the return flight.)
If you don't want to wait for jet lag to naturally take its course, Lockley and Zeitzer say it's possible to accelerate the transition and reset your internal clock using strategically timed light and dark exposure.
How to treat jet lag:
1. Expose yourself to light and dark at the right times.
"The light-dark change is the cause of jet lag and therefore has to be the basis of any treatment of jet lag," says Lockley, who is also a jet lag and shift-work adviser for NASA.
However, he adds, the lighting required to get your circadian rhythm back on track will depend on the number of time zones traveled, the direction of travel, your sleep chronotype, the time of day you're flying, and more. This means that generic advice to "get sunlight once you land" or "avoid napping at your destination" will not work for everyone—and can actually make jet lag worse if it shifts you in the wrong direction.
Instead, you need to do the mental math of calculating what time your unique body thinks it is, what time it really is, and how to bring those two things closer together.
To make this process easier, Lockley created Timeshifter—an app that uses circadian science to formulate individualized jet lag plans for travelers. After inputting information on your flight, preferred sleep timing, chronotype, and preferences such as supplement or caffeine use, the app tells you exactly when to sleep, nap, see some light (by going outside, turning on an overhead light, or using electronics), and keep things dark (by drawing the shades or wearing sunglasses).
On average, Lockley says, those who follow the app's advice are able to shift to the new time zone three to four times faster than they would normally. (If travelers can't do everything perfectly, he says that following the plan as closely as you can will result in less jet lag than doing nothing.)
2. Incorporate caffeine and melatonin.
Lockley adds that melatonin, which is also able to reset the circadian clock, and stimulants like caffeine can also help expedite the adjustment process and management of jet lag—but again, they must be used at the right times, based on your circadian rhythm and sleep timing. Here are our favorite sleep supplements.
These tools can also have multiple interacting benefits. For example, Lockley explains that caffeine use can not only keep you awake but help you to stay awake long enough to see light at the right time, while melatonin may help you sleep and shift the clock but also help you to avoid light at the right time (just be careful as it can disrupt your hormones and cause grogginess).
3. Keep up with healthy habits.
While eating nutritious foods, drinking plenty of water, avoiding alcohol, and exercising each day won't treat the underlying cause of jet lag, they can help you recover from some of the other pains of long-haul travel.
How to prevent jet lag.
As you've probably gathered by now, it's impossible to prevent or avoid jet lag altogether. If you have a long trip coming up, do your best to build in some buffer time for you to get back in the swing of things upon landing. Packing an eye mask, portable white noise machine, or another favorite relaxing product can also help you adjust to the unfamiliar sleep environment.
As for the flight itself, drinking plenty of water, moving around and stretching if you can, and skipping the booze should all help make the experience a bit more pleasant and set you up for success upon landing.
The bottom line.
Jet lag happens when we travel to a new time zone where the light cycle is mismatched with our circadian rhythm. Our bodies will naturally catch up to the new time—but it will take a few days. Expediting the process requires strategically exposing yourself to light and darkness at your destination. When done correctly, light-dark exposure can help you more quickly snooze into quality sleep on the road—exactly when you need it.