What Really Works for Jet Lag?

Written by: Denise John, PhD


Published on: May 30, 2024

Photo courtesy of Eren Sarigul

If you’re traveling somewhere that’s more than a three-hour time difference, you’re probably going to experience some form of jet lag. The fatigue, irritability, difficulty sleeping, and poor digestion can give a general sense of feeling off during the first days of a trip.

Mitigating jet lag is all about light—and the time that you’re exposed to it. Other efforts (like hydration, sleep, and limiting caffeine) help provide a healthy foundation for you to adapt more easily but don’t address jet lag at its core.


Light—when it enters through our eyes and signals to the brain that it’s day or night—controls our circadian clock, or sleep-wake cycle. In response, our bodies release hormones and neurotransmitters in sync with the time of our internal clock. For example, when you’re regularly exposed to light during the day and darkness at night, testosterone and cortisol are released at peak levels in the morning, telling your body that it’s ready to start the day. And GABA and adenosine, two naturally occurring, calming chemicals, are highest in the evening, signaling that it’s time to rest for the night.

When we travel across time zones, our internal clock is saying one time and the external clock is giving another—they’re out of sync. That means our bodies are secreting hormones and neurotransmitters out of alignment with day and night, leading to an array of untimely symptoms. “When your hormones and your neurotransmitters are off, it’s going to impact your mood, energy, appetite, digestion, and cognitive ability,” says sleep coach Kelly Murray, who regularly helps her clients manage jet lag when traveling.


Adjusting your external light cues to the time zone that you’re traveling to can help you shift your circadian clock to match the external world, resulting in less jet lag.

According to Murray, it’s best to start before your trip begins. “It generally takes about a day to a day and a half to shift your circadian rhythm by one hour,” she says. (Everyone’s circadian clock and sleep patterns are different, though, so this can vary.) That means you’ll need to adjust your sleep-wake cycle by 60 minutes, ideally, each day prior to your trip.

For example, if you’re traveling from New York to London—flying west to east, to a destination that will be five hours ahead—Murray says you’ll want to start adjusting three to five days prior to the trip. This will help you begin to shift your circadian clock so when you arrive it’s not five hours out of sync with your destination’s time. Here’s what she recommends doing in this scenario.

  • Wake up early and seek bright light. Murray says you’ll need to adjust by waking up earlier—a half hour to an hour earlier each day. And immediately expose yourself to bright light (preferably sunlight), ideally for 30 minutes but for at least 10.
  • Go to bed early and minimize light. Murray says wearing blue-light-blocking glasses—ones that block at least 95 percent of the blue light—two hours before your target bedtime can help you feel sleepy earlier. “This tells your body that it’s nighttime, and then your body will start releasing melatonin sooner,” she says.

When you’re traveling in the reverse direction—east to west—Murray says you’ll want to do the opposite: wake up later and get to bed later. “To help your body stay awake later, expose yourself to blue light at night,” says Murray. “You can buy a blue-light box and sit in front of it 30 to 60 minutes before bedtime.” (We also like the BIOS Lighting Skyview 2 lamp for this same purpose.)


When it comes to adjusting light and sleep on the plane, Murray says, the goal is to sync your internal clock with your destination’s time zone on your flight. To do this, you want to control light exposure as much as possible. She recommends two key items: an eye mask, and a blue-light-emitting device. Use the eye mask to block out light when it’s nighttime at your destination—this will help signal to your brain that it’s time to rest.

Conversely, when it’s daytime at your destination, she says to expose yourself to as much natural light as possible. If you can’t (maybe you’re not in a window seat or it’s dark out), optimize your artificial light exposure. You can do so with your phone, iPad, or laptop—by exposing yourself to the blue light of the device by watching a movie, scrolling, or reading. You can also use blue-light glasses, which will create exactly the opposite effect of wearing an eye mask.

Murray says when traveling eastbound, stay awake on the plane. That way, you have built up plenty of sleep pressure to help you to fall asleep earlier than you normally do the first day. When traveling westbound, she recommends sleeping on the plane to reduce your sleep pressure and help you stay awake later.


Murray says that you can support your body in shifting its circadian clock before, during, and after your flight. Here are six things she recommends doing.

  1. Get a light-scheduling app. Keeping track of your jet lag plan can be a mind twist, but it’s the most important thing—it’s vital to shifting your circadian clock. “Usually what I recommend when people are doing those long-haul flights is to download this app called Timeshifter,” says Murray. “It does all the calculations for you.” You input your travel itinerary (and some information about your sleep patterns, which is also factored in) and it provides optimal times for light exposure, sleep, and caffeine use. “Using the Timeshifter app was such a game changer for me,” she says.
  2. Sleep well and limit stress. “Before a trip, if your body is well rested, it is more adaptable,” Murray says. She also recommends managing your mental and emotional stress before your travel. This includes packing in advance and giving yourself plenty of time to get to the airport. “When you’re stressed, that can negatively impact your circadian rhythm because your body starts to produce excessive amounts of cortisol.” This can make you more alert, even around bedtime.
  3. Eat a balanced diet and limit caffeine and alcohol. “I know it’s hard when you’re on vacation, but staying away from sugary foods is ideal,” says Murray. The sugar spikes can cause fatigue, especially when they’re fluctuating downward. She also recommends limiting caffeine and alcohol—they alter chemicals, like adenosine, that control sleep and can disrupt your sleep-wake cycle.
  4. Stay hydrated. “When you’re in flight, you want to stay hydrated,” she says. Dehydration can be a physical stressor that can make it harder for your body to adapt to the time change. Water and electrolyte packets—we like CURE—are helpful.
  5. Nap strategically and move your body. “Naps can actually delay the adjustment of your circadian rhythm,” says Murray. “It’s better to use exercise as a tool for staying alert.”
  6. Use melatonin wisely. Murray says that if you’re going to experiment with melatonin, the time you take it is key. If it’s at the wrong time, it can disrupt your circadian clock even more instead of helping. “A general rule of thumb: If you’re trying to advance your circadian rhythm , you can take a small dose of melatonin, about 0.5 milligrams, around two hours before your desired bedtime to help induce a little sleepiness,” she says. This will mimic the body’s natural rhythm for melatonin secretion.

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