A Trusted Friend in a Complicated World
By Lisa Lombardi
Updated on Jan. 29, 2026
Yes, it’s possible to feel refreshed after a long flight! Steal these insider hacks to cross time zones like a pro.
Have a work trip or vacation on the horizon? If you will be crossing time zones, you’re probably already wondering how to avoid jet lag so you don’t feel like a zombie. Time is precious, after all, and the last thing you want to do is to start or end your trip tired, wired or just plain crabby.
Beating jet lag is about getting your body in sync with a new time zone, and the earlier you start, the better you’ll feel. To find out how to avoid jet lag, I interviewed five sleep scientists for their go-to strategies and advice on taking a long flight. Read on to learn the tactics sleep experts use to adjust to local time as easily as possible—and how you can too.
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We all have a central circadian clock in our brain, and jet lag happens because our clock isn’t synced to local time, explains Helen Burgess, PhD, co-director of the Sleep and Circadian Research Laboratory in the Department of Psychiatry at the University of Michigan in Ann Arbor. So to avoid jet lag, the scientist takes a cue from her own research and shifts her body clock closer to local time before she takes off. “Three days before I leave, I start shifting my clock,” she says. This move helps make international travel easier, in particular.
Here’s the drill:
That’s what neurologist Fouzia Siddiqui, MD, a sleep specialist with Sentara Health in Harrisonburg, Virginia, does. “Light is a strong cue to reset our circadian rhythm,” she says. “Get bright sunlight early in the day if you’re traveling east (to wake up earlier) or late in the day if traveling west (to stay up later).” This helps adjust your body clock so local time doesn’t seem so foreign.
Two to three hours before we wake up, our melatonin levels are at their lowest. This is called the “crossover point”—when your body is switching from sleep to wake. “Getting light before that point is going to shift you later, and getting it after that time will shift you earlier,” Burgess says.
So if you fly from New York to Paris and land at 8 a.m., it’s 2 a.m. back home (and in your confused brain). If you normally get up at 7 a.m. Eastern Time (ET), your crossover point is around 4 a.m. ET. So you don’t want light before that time. Ideally, plan your flights to land more like 10 a.m. or later, which is after the crucial crossover point in your circadian clock cycle.
Another way to control light exposure early in the day if you’ve just jetted east is by rocking “blue blocker” glasses. ”They specifically block blue wavelengths of light, and it’s the blue wavelengths that our circadian system is the most responsive to,” Burgess says. “I had a conference in Singapore and went through Seoul, South Korea. I had my jet lag plan, and I knew when I landed in Seoul, this was a time when light was not going to be helpful to me. So I had my blue blockers on in the airport.” If you need to be outside at the “wrong” time, sunglasses will block UV rays.
Enjoying a hearty breakfast in the morning when you land in your new time zone is a surprising trick for reducing jet lag, according to a 2023 study by Northwestern University researchers. As much as possible, stick to that local breakfast time the whole time you’re away. As the researchers noted, “you might feel that you recover from the jet lag faster if you really focus on eating breakfast at a fixed time every day.”
There isn’t a one-size-fits-all formula for how to avoid jet lag, so the Timeshifter app—designed by an MD who consulted on circadian rhythms for NASA—gives you “a customized plan for adapting to a new time zone based on your flight, preferred sleep times, chronotype and other preferences,” says co-founder Steven Lockley, PhD. You start before you even board the plane, taking small steps to make the transition to a different time zone easier.
It’s a go-to tool for internal medicine physician Austin Perlmutter, MD, author of Brain Wash: Detox Your Mind for Clearer Thinking, Deeper Relationships, and Lasting Happiness, who likes that it tells you when to sleep, when to use caffeine and when to get light exposure. “My wife and I use Timeshifter when we travel,” he says. “It’s an excellent way to prepare your body for the destination.”
Flying can dehydrate you because planes are super dry. The humidity level of an aircraft cabin can sink as low as 10%, according to a report in the Journal of Medicine. Our bodies, meanwhile, are most comfortable in an environment with 40% to 50% humidity. As you could probably guess, being dehydrated can make jet lag feel much worse, since it can give you a splitting headache, lightheadedness and other less-than-fun symptoms.
So make sure you’re already hydrated when you board your flight and drink up during your flight, even if it means you have to hit the bathroom constantly. “Drink plenty of water on the plane and limit alcohol and caffeine,” Dr. Siddiqui says. “Dehydration and alcohol interfere with sleep patterns.”
The problem with grabbing a “quick catnap” once you check in to your hotel is that your (exhausted) body will hijack your plan. How many times have you arrived somewhere, closed those blackout curtains to “rest your eyes” … and passed out until dinnertime? Yikes! A better bet: “Power through until it’s time to go to bed in the new time zone,” advises Jessica Fink, LCSW-S, a sleep specialist at Jessica Fink Therapy in Austin, Texas.
If you’re struggling to stay alert at your destination, it’s OK to turn to caffeine. But don’t go overboard. The Centers for Disease Control and Prevention (CDC) recommends people with serious jet lag take 200 milligrams of caffeine (about the amount in a Starbucks dark roast short coffee) every four hours. Meanwhile, Timeshifter advises a ballpark of 50 milligrams of caffeine every two hours. Just be sure to stop at least eight hours before bedtime so the buzz doesn’t mess with your sleep.
One simple secret to giving your body space to acclimate is to not overbook your first day there (or home). Burgess finds this rule helpful when she crosses many time zones to visit her family in Sydney, Australia. “ I usually try not to have anything major happening that first day that I’m there,” she says, “because I just know I’m going to be tired.” So on that trip from New York to Paris, maybe save your Eiffel Tower climb or exploration of hilly Montmartre for later in the week.
It’s wild to realize you are having a morning café au lait and buttery croissant when you would be deep in REM sleep back home. Try to push it out of your mind. “Don’t think about what time it is back home, or you’ll psych yourself out,” Fink says.
Yup, one big element of learning how to avoid jet lag is mentally embracing your new (temporary) body clock once you land. Fink adopts this philosophy: “It doesn’t matter what time it is back home,” she says. “The time is whatever it is where you currently are.”
Reader’s Digest has published hundreds of travel stories that help readers explore the world safely, easily and affordably. We regularly cover topics such as the best places to visit (and the best times to visit them), tips and tricks to zoom through airport security, flight-attendant secrets, hotel-room hacks and more. We’re committed to producing high-quality content by writers with expertise and experience in their field in consultation with relevant, qualified experts. We rely on reputable primary sources, including government and professional organizations and academic institutions as well as our writers’ personal experiences where appropriate. We verify all facts and data, back them with credible sourcing, and revisit them over time to ensure they remain accurate and up to date. Read more about our team, our contributors and our editorial policies.
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