How to Beat Jet Lag

Updated August 2026 · Vacation Checklists

Jet lag is not ordinary tiredness. It is a mismatch between the clock inside your head and the clock on the wall, and the single strongest tool for fixing it is light. Getting bright light at the right hours, and blocking it at the wrong ones, shifts your body clock faster than sleep aids, hydration, exercise, or meal timing. Everything else on this page is a supporting act to that one lever.

Still packing? Our free packing list generator builds your list, and the small jet lag kit near the bottom of this page drops straight onto it.

Updated August 2026. This is general travel information, not medical advice. We describe categories of options rather than doses, because what suits you depends on your age, your health, and any other medicines you take. Ask a pharmacist or your doctor before taking anything, including supplements. Background on circadian rhythms comes from the National Institute of General Medical Sciences and travel health guidance from the CDC's travelers' health site.

Why Jet Lag Happens

Your body runs on an internal clock in the brain, and it keeps a schedule for far more than sleep. It sets your core body temperature, your alertness, your hormone release, your digestion, and your bathroom habits. That clock does not fly. It stays on home time and drifts toward local time at a slow, fixed rate.

So when you land in Rome at 8:00 am after a flight from Chicago, your brain is running the 1:00 am program. It is releasing the hormones for deep sleep, running your body temperature at its overnight low, and shutting down your digestion. The city outside wants breakfast and a walk. That gap is jet lag, and the symptoms follow from it: broken sleep, daytime fog, a headache, no appetite at meal times and a raging one at 3:00 am, and a stomach that has opinions.

The clock resets using signals from the outside world. Light is by far the loudest of those signals. Meal timing, activity, and social cues nudge it. Light moves it.

Which Levers Actually Move Your Clock

Not every popular jet lag tip does the same job. Some shift the clock. Some only make you feel better while the clock catches up on its own. Both are useful, but only if you know which is which.

Hydration deserves a plain statement, because it gets sold as a jet lag cure. Cabin air runs very dry, often under 20 percent relative humidity, so you will feel parched, scratchy, and headachy after a long flight. Drinking water fixes that discomfort. It does not move your body clock by one minute. Drink because you will feel better, not because it treats jet lag.

How to Beat Jet Lag Flying East vs West

Direction is the biggest factor in how hard your trip will be, and it is not close. Flying east is harder than flying west, and the reason is built into human biology.

Left alone in a room with no clocks and no daylight, most people settle into a day that runs slightly longer than 24 hours, averaging around 24.2 hours. Your clock naturally wants to drift later. Every morning, light pulls it back into line.

Flying west asks your clock to do the thing it already wants to do. You need to stay up later and sleep in later, which is a phase delay. Your body leans into it. Flying east asks for the opposite, an earlier bedtime and an earlier wake, which is a phase advance. You are working against the natural drift, so it goes slower and feels worse.

Two practical results follow:

• Westward, you recover about 1.5 time zones per day. You will feel sleepy embarrassingly early and wake at 4:00 am for a few days, but daytime function is usually decent.
• Eastward, you recover about 1 time zone per day, sometimes less. You will lie awake at a local bedtime that your body reads as mid afternoon, then feel wrecked at breakfast.

There is a stranger effect on very long eastward hops. Cross eight or more zones east and your clock sometimes gives up on advancing and shifts the long way around instead, delaying by 16 hours rather than advancing by 8. Sleep researchers call it antidromic re-entrainment. It is one reason a Los Angeles to Tokyo trip can feel disproportionately brutal, and it is a strong argument for taking the light timing seriously rather than winging it.

The Light Timing Table

Here is the part that does the work. Light in the few hours after your body's temperature low pulls your clock earlier. Light in the few hours before that low pushes it later. Your temperature low sits roughly two hours before your usual wake time at home, and it travels with you.

That is why simply chasing sunshine on arrival can backfire. Land in Paris at 8:00 am from New York and that morning light hits before your body's temperature low, which pushes your clock later, the exact opposite of what you need.

The table below assumes a 6 time zone shift and a normal wake time of 7:00 am at home. All times are destination local time. If you wake at 6:00 am at home, slide everything one hour earlier. If you cross fewer zones, compress the schedule into fewer days.

Two notes on what "bright" means. Outdoor daylight, even under cloud, runs from about 1,000 to over 10,000 lux. A well lit room runs 100 to 500. That gap is enormous, which is why 20 minutes outside beats an hour by a window, and why a walk is the most effective jet lag intervention available to you.

"Avoid light" does not mean sitting in a dark room. It means sunglasses outdoors, hat brim down, curtains half drawn, no bright overhead lights, and your phone on its dimmest setting. You are lowering the signal, not eliminating it.

A Worked Example: New York to Paris

Take a family flying JFK to Paris, 6 zones east. The flight leaves at 7:00 pm Eastern and lands at 8:30 am Paris time. Normal wake time at home is 7:00 am, which puts the body's temperature low around 5:00 am New York time. In Paris, that is 11:00 am on arrival day.

So on the day you land:

• 8:30 am to 11:00 am Paris time. Sunglasses on from the moment you step outside the terminal. Get to the hotel, keep the room dim, do not sit in a sunny cafe. Bright light in this window would push your clock the wrong way.
• 11:00 am to 5:00 pm. Sunglasses off, get outside, walk. A two hour walk beats a two hour nap by a wide margin.
• Around 3:00 pm. If you are collapsing, a 25 minute nap is fine. Set an alarm and take it before 3:00 pm.
• After 8:00 pm. Dim everything. Screens on night mode and low brightness.
• 10:00 pm to 10:30 pm. Bed, even if sleep takes an hour to arrive.

Day two, everything moves 90 minutes earlier: sunglasses until 9:30 am, then out into the light. Day three, out of the door at 7:00 am. By day four or five you are running on Paris time, which fits the rough one day per zone rule for a 6 zone eastward trip.

Compare that with the default approach, which is to arrive, sit in the sun outside a cafe at 9:00 am because it is Paris and the light is beautiful, then nap from 2:00 pm to 5:00 pm. That morning light delays your clock, the long afternoon nap burns the sleep pressure you needed for the night, and you are awake at 2:00 am, wide eyed, extending the whole thing by two or three days.

Pre-Adjusting Before You Leave

Shifting your sleep schedule at home before departure genuinely works. It is also impractical for most people, and we would rather say that plainly than pretend otherwise.

The method: for an eastward trip, move your bedtime and wake time 30 to 60 minutes earlier per day for the three days before you fly, and get bright light immediately on waking. For a westward trip, push both later by the same amount and get bright light in the evening.

Three days of that buys you two to three zones of head start, which is a real saving on a 6 zone trip. The problem is the three days before a big trip are the three days you are finishing work, doing laundry, and arguing about the suitcase. Waking at 5:00 am on the day you also have to file a report is a lot to ask.

An honest compromise that costs almost nothing:

• Shift your schedule by one hour total, on the night before departure only.
• Get outside for 20 minutes on departure morning if flying west, or keep the morning dim if flying east.
• Book the flight so you arrive in daylight rather than at 11:00 pm, which does more for you than three days of alarm clocks.

If your trip is a big one, a wedding, a race, a presentation, or a two week vacation you are not repeating, the full three day pre-adjust is worth it. For a routine trip, it is not.

What to Do on the Plane

The plane is where most jet lag advice goes wrong, because it treats the flight as the cure. It is not. It is the setup for what you do in the first 48 hours on the ground.

Set your watch and phone to destination time at the gate. Not on landing. Doing it before you board changes how you think about every decision on the flight, and it is free. Every mental calculation from then on is in local time.

Sleep on the destination's schedule, not on the airline's. Cabin crew serve dinner when it suits the operation, and they dim the cabin when it suits the route. If it is 3:00 am at your destination, that is a sleep window whether the cabin is bright or not, so use the eye mask. If it is 2:00 pm at your destination, stay awake even though dinner has been cleared and everyone around you is asleep.

Bring the gear that makes the schedule possible. A real eye mask, foam or silicone earplugs plus noise canceling headphones, and a neck pillow you have actually tested. Sleeping upright is a skill and equipment problem, not a willpower problem. Our travel essentials checklist covers the whole kit.

Drink water, and know what it is doing. Cabin humidity is very low, so you will feel better hydrated. That is a comfort win, not a clock win. Alcohol is the one to think about honestly: it may help you fall asleep, and it makes the second half of the night worse, exactly the half you needed.

Get up and move every couple of hours. Circulation, stiffness, and a modest alertness effect. It will not shift your clock, but it makes the arrival day survivable.

One planning note that saves the whole first day: on a long haul arrival, immigration, baggage, and transfer can eat two hours before you reach your hotel. Build that in, and build in the check in time on the outbound too. Our guide on how early to arrive at the airport has the current numbers for domestic and international departures.

Melatonin: What the Evidence Actually Supports

Melatonin is a hormone your brain releases in the evening as darkness falls. It is not a sedative. It is a time signal, telling your body that night has begun. Taken as a supplement, it can nudge the clock in the same way a light signal does, in the opposite direction.

What the research supports reasonably well:

• It helps most for eastward travel across roughly five or more time zones, which is exactly the direction that is hardest to fix with light alone.
• The timing of the dose matters far more than the amount. Taken in the local evening before your target bedtime, it advances the clock. Taken at the wrong hour, it can shift you the wrong way or simply do nothing.
• The effect is moderate, not dramatic. It is a useful addition to a good light schedule, not a replacement for one.
• More is not better. Higher amounts do not shift the clock further, and they raise the chance of grogginess the next morning.

What we will not do is tell you how much to take or exactly when. That depends on how many zones you crossed, your own sleep timing, your age, and any other medicines you take. Ask a pharmacist or your doctor, and do it before you leave rather than in a foreign pharmacy at midnight. Melatonin also interacts with several common medications, including blood thinners, some blood pressure drugs, and diabetes medication, which is another reason to ask.

Two more practical points. In the United States melatonin is sold as a dietary supplement rather than a regulated drug, so actual content has been found to vary widely from the label. Look for a third party quality seal. And in many countries, including much of Europe, melatonin is prescription only, so you cannot count on buying it at your destination.

Caffeine Timing

Caffeine does not move your body clock. It blocks the receptors that make you feel sleepy, so it hides the problem for a few hours and then hands it back. Used carelessly, it is the most common reason a good light plan fails.

The number that matters is the half-life, which is roughly 5 to 6 hours in most adults, longer if you are older, pregnant, or taking certain medications. That means a large coffee at 3:00 pm still has about half its caffeine working at 9:00 pm and a quarter of it at 3:00 am.

A workable rule for adjustment days:

• Use it in the destination morning, in the same window where you are seeking light. It reinforces the schedule.
• Cut it off 8 hours before your target local bedtime. For a 10:30 pm bedtime, that is 2:30 pm.
• Do not use it to push through a westward evening, where the light itself is doing the delaying work for you.
• Watch for the hidden sources: green tea, cola, iced tea, chocolate, and some over the counter headache tablets.

Naps: The 20 Minute Rule

A nap on arrival day is not cheating. The wrong nap is the single fastest way to blow up your first night.

Sleep runs in cycles of about 90 minutes, moving from light sleep into deep slow wave sleep and then into REM. Wake up out of light sleep and you feel refreshed. Wake up out of deep sleep and you get sleep inertia, that heavy, confused, angry feeling that can last an hour.

Two rules on top of the length. No naps after 3:00 pm destination time, because the sleep pressure you spend in the afternoon is the pressure you needed at 10:30 pm. And set an alarm across the room, because the whole point of a 20 minute nap is that it stays 20 minutes.

The strongest alternative to a nap is the one nobody wants to hear on arrival day: go outside and walk in the daylight for 30 minutes. It hits alertness and the clock at the same time, which no nap does.

How Long Does Jet Lag Last?

The rule of thumb is one day of recovery per time zone crossed. Cross 6 zones, expect about six days to feel fully normal. It is a decent planning number, and it has real limits worth knowing.

Where the rule holds up:

• It is roughly right for eastward travel of 4 to 8 zones.
• It is useful for planning. If your presentation is on day two after a 7 zone eastward flight, you now know to write it before you fly.

Where it breaks down:

• Westward is faster. Figure 1.5 zones per day, so 6 zones west is about four days, not six.
• It is an average, and people vary enormously. Age, whether you are an early riser or a night owl, sleep quality on the flight, and simple genetic variation all move it. Two people on the same flight can differ by days.
• It assumes you are handling light correctly. Chase sunlight at the wrong hours and you can extend recovery well past the rule. Follow the table above and you can beat it.
• The first two days are not the worst. Days two and three are often harder than arrival day, because arrival adrenaline has worn off and the sleep debt has stacked up.
• Symptoms fade before the clock finishes. You usually feel fine several days before every rhythm has fully re-entrained, which is fine for a vacation and matters more for athletes and shift workers.

The Jet Lag Kit

Small, cheap, and it fits in a personal item. Add these to your list:

Sleep gear - [ ] Contoured eye mask that does not press on your eyes - [ ] Foam or silicone earplugs, plus noise canceling headphones - [ ] Neck pillow you have tested at home - [ ] A pair of thin socks for the cabin

Light control - [ ] Sunglasses, kept in your personal item and not the overhead bin - [ ] A hat with a brim - [ ] Binder clips or clothespins for hotel curtains that never quite close

Schedule tools - [ ] A watch or phone alarm set to destination time before boarding - [ ] A second alarm for ending naps, placed across the room

Comfort - [ ] Empty water bottle to fill after security - [ ] Lip balm and a small moisturizer for dry cabin air - [ ] Any supplement you have cleared with a pharmacist, in its labeled container

Drop the whole kit onto your trip list with the packing list generator, then fill in the rest of the bag from our travel essentials checklist.

Short Trips: Sometimes You Should Not Adjust

If you are away for two or three days, adjusting is often the wrong call. You will spend the whole trip half shifted and then pay for it again on the way home.

Instead, stay on home time. Schedule your important meetings during the hours that are daytime back home, keep your meals near home time where you can, and use blackout and light control to protect a home time sleep window. Business travelers who fly the same route often build their whole trip around this.

The cutoff is roughly three days. Longer than that, adjust properly. Shorter than that, stay on your own clock and take the win on the return leg.

Frequently Asked Questions

How do you get rid of jet lag fast?

Control light before anything else. Get bright outdoor light during the hours that push your clock in the direction you need, and block light hard during the hours that would push it the wrong way, using sunglasses and dim rooms. Then sleep and wake on destination time, keep naps to 20 minutes, and cut caffeine 8 hours before your target bedtime.

Is jet lag worse flying east or west?

East, clearly. Your body clock naturally runs slightly longer than 24 hours, so it prefers to drift later, which is what westward travel asks for. Eastward travel asks you to advance the clock against that drift, so recovery runs at about one time zone per day going east versus roughly 1.5 going west.

Does melatonin actually work for jet lag?

The evidence supports a moderate benefit, mainly for eastward travel across five or more time zones, and the timing of the dose matters far more than the amount. It works as a time signal rather than a sedative, so it supports a good light schedule rather than replacing one. Ask a pharmacist or your doctor about whether it suits you and when to take it, since it interacts with several common medications.

How long does jet lag last?

Plan on about one day per time zone crossed heading east, and about 1.5 zones per day heading west. So 6 zones east is roughly six days and 6 zones west is roughly four. It is an average with wide personal variation, and handling light correctly can beat it while chasing sunlight at the wrong hours can extend it.

Should I nap after a long flight?

A 20 minute nap is genuinely helpful. Anything from 45 minutes to two hours wakes you out of deep sleep, leaves you groggy, and spends the sleep pressure you needed that night. Set an alarm, keep it under 30 minutes, and take nothing after 3:00 pm local time.

Does drinking water prevent jet lag?

No. Cabin air is very dry, so drinking water makes you feel considerably better on and after a long flight, but dehydration and jet lag are separate problems. Hydration treats the headache and the scratchy throat. Only light, sleep timing, and to a lesser extent melatonin move your body clock.

Can I adjust to a new time zone before I travel?

Yes, and it works. Shift your bedtime and wake time 30 to 60 minutes per day for three days before departure, earlier for eastward trips and later for westward ones, with bright light on waking or in the evening to match. It is genuinely impractical for most people in the week before a trip, so if you only do one thing, shift by an hour the night before and book an arrival in daylight.

What is the best time to arrive to reduce jet lag?

Landing in the morning or early afternoon at your destination is usually best, because you get a full day of correctly timed light before your first night. A late evening arrival on an eastward trip is the hardest, since you go straight to bed at a time your body reads as mid afternoon. Where you have a choice of flights, arrival time is worth more than a slightly better seat.

The Short Version

Jet lag is a clock problem, so fix it with the signal your clock listens to. Set your watch to destination time at the gate, sleep on the destination's schedule in the air, and then run the light table: block light in the wrong window with sunglasses and dim rooms, and get outside in the right one. Expect east to take about a day per zone and west to run faster. Keep naps to 20 minutes, stop caffeine 8 hours before bed, and ask a pharmacist about melatonin before you leave rather than after you land. For a trip under three days, do not adjust at all.