Does Dimming the Cabin Lights Actually Help Fliers with Jet Lag?

The changing cabin lights on a long-haul flight can be useful for sleep-schedule adjustments—if you’re strategic about which flights, of course.

A row of non-intense blue lights stretching down the length of an airline cabin

Putting cabin-lighting shifts to good use requires a strategy.

Courtesy of Icelandair

When Etihad unveiled its new Airbus A350 in 2022, the carrier touted some of the new features, including business-class pods with lie-flat seats, kid-friendly programming, and LED cabin lighting it claimed would help lessen the effects of jet lag.

In the press release announcing the new long-haul plane, the airline said the lighting was designed to “emulate natural ambient light” and “provide an optimum environment for sleeping.” In practice, that meant that, following meal service, staff gradually dimmed the lights to help passengers fall asleep and then slowly turned them back on to gently rouse travelers for another meal before deplaning. Similarly, when JetBlue unveiled its reimagined Mint product for transatlantic travel, it introduced custom lighting that transitioned to a deep blue after in-flight dining, ostensibly to promote sleep, and switched to sunrise hues to slowly wake fliers up before breakfast service.

Flying long distances across time zones can be challenging for travelers, particularly as they try to maintain a semblance of a regular sleep schedule. So custom lighting to help with jet lag seems like a lovely customer-service touch. However, Dr. Chelsea Perry, founder of Sleep Solutions, a sleep medicine clinic in Massachusetts, said many factors determine the best times to fall asleep en route to combat jet lag, “including the direction of travel, departure and arrival times, and the time zones you’re crossing.” Given all that, the one-size-fits-all lightning strategy adopted by airlines will work only for some long-haul flights.

However, there are ways you can use the lighting to your advantage and measures you can take to lessen the impact of jet lag. Here’s what you need to know.

What is jet lag, and what causes it?

According to Dr. Catherine Darley, an expert on sleep disorders and founder of skilledsleeper.com, our body’s clock is closely tied to our environment. Signals such as light, darkness, and temperature changes, along with behaviors such as meal times, activity levels, and social interactions, program us to be active during the day and asleep at night. Shifting away from an established sleep schedule is challenging.

“Our body clock can shift, at most, an hour a day,” Darley said. “This is why when we have jet lag, we’re essentially working against our body clock, which is still back in our original location, and giving these environmental and behavioral cues at radically different times in our new destination.”

For that reason, according to Cleveland Clinic, a nonprofit academic medical center, jet lag can make you “feel out of sorts due to an abrupt change in your body’s internal clock.”

A view of an airplane wing through a window, with purplish lighting in the cabin

Depending on the direction in which you’re flying and the time of your flight, dimmed cabin lighting can be a big help in resetting your body clock.

Courtesy of Shutterstock

When does the science behind airlines’ cabin-lighting shifts work?

Dr. Shelby Harris, a licensed clinical psychologist specializing in behavioral sleep medicine, said the scenarios in which dimming the lights work best are on flights that depart in the evening and fly through the night. During that timeframe, the strategy can help passengers rest during their natural sleeping hours.

“When flying east, especially on long-haul flights, passengers ‘lose’ time and often arrive at their destination in the morning,” Harris said. “Dimming the lights after the first meal can help them fall asleep earlier, making it easier to wake up closer to their destination’s morning time.”

However, when airline crews turn off the lights immediately after the first meal service during flights that depart in the morning or afternoon, it could throw passengers’ sleep cycle out of whack.

By flying west, travelers generally gain time, said Harris, and that extra time helps passengers stay awake longer to adjust to the new time zone. “Turning the lights off too early could make it harder to adjust to the extended day and get to sleep later,” Harris noted.

She added that on flights that cross several time zones, a more nuanced lighting strategy—as opposed to a simple on-off strategy after the first meal service—could help passengers gradually adjust to their destination’s time zone.

Still, she said, turning off the lights often creates a more restful environment for passengers.

“While not a cure-all, this approach, along with pretrip sleep adjustments and sunlight exposure upon your arrival, can nudge your internal clock closer to your destination’s time zone,” Harris said.

How to combat jet lag, according to doctors

If possible, Perry said it’s a good idea to start gradually shifting your sleep schedule toward the new time zone about three days in advance of a trip.

“If you’re heading somewhere ahead in time zones, like from New York to London, try going to bed an hour earlier each night,” Perry said. “For destinations behind your current time, like flying from Los Angeles to Tokyo, staying up a bit later can help ease the transition.”

That math plays into when you should sleep on the flight, too. Harris says the “best time to sleep on a long flight depends on your direction and timing. If you’re flying east, like from New York to London, try to sleep early in the flight to match what your bedtime would be at your destination. For westward flights, like from London to New York, stay awake longer and sleep later in the flight to align with the local time when you land.”

Harris added that you should consider your arrival time, too. If you’re landing in the morning or early afternoon, sleep during the flight to feel more rested. If you’re landing in the evening, try your best to stay awake on the plane and sleep when you get there.

Perry also recommends trying to sync your in-flight meals with the local time at your destination, as eating at intervals aligned with your destination can signal your body to adjust to the destination’s new schedule. Drinking plenty of water is also crucial, as dehydration can worsen the effects of jet lag. Similarly, she recommends avoiding alcohol and caffeine, as these can interfere with your sleep patterns and make it harder for your body to adjust. She added that when you arrive, spending time in natural light can help reset your internal clock. Sunlight is a powerful cue for your body’s circadian rhythms, so getting outside and being active during the day can facilitate adaptation.

“The more you can align your activities—like sleeping, eating, and spending time outdoors—with the local time, the quicker you’ll reduce the impact of jet lag,” Perry said.

Bailey Berg is a freelance travel writer and editor, who covers breaking news, trends, tips, transportation, sustainability, the outdoors, and more. She was formerly the associate travel news editor at Afar. Her work can also be found in the New York Times, the Washington Post, National Geographic, Condé Nast Traveler, Travel + Leisure, the Points Guy, Atlas Obscura, Vice, Thrillist, Men’s Journal, Architectural Digest, Forbes, Lonely Planet, and beyond.
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