How to avoid jet lag: the things that actually work (and the things that are travel placebo)

I once arrived in Tokyo after a 20-hour journey from Helsinki, lay down on the hotel bed at 4pm “just for a moment,” and woke up at 2:37am with no memory of the last several hours and a profound sense of confusion about what country I was in, what year it was, and whether I’d eaten.

I had not eaten. I found a vending machine in the hotel corridor and stood there in my travel clothes, blinking at a can of corn soup, while a businessman in a suit gave me a very polite wide berth.

That was year one of the nomad life. I have since crossed enough time zones to have an opinion about what actually works, and the corn soup incident does not happen anymore. Here’s what changed.

First: what jet lag actually is

Jet lag is your circadian rhythm, the internal clock that regulates when you sleep, when you’re alert, when you’re hungry, and when your body does its maintenance, being out of sync with your new time zone.

Your body clock is set primarily by light, specifically by cortisol and melatonin signals triggered by daylight and darkness. When you fly east or west across multiple time zones, the clock doesn’t update instantly. It updates at a rate of roughly one time zone per day. So a 9-hour time difference (Helsinki to Tokyo, say, or London to New York in reverse) takes about nine days to fully adjust.

What you’re working against isn’t tiredness from the flight. It’s a biological timing mismatch. Which is why sleeping on the plane doesn’t solve it, why coffee doesn’t solve it, and why “just push through the first day” works for some trips but makes others worse.

Knowing this reframes the strategy.

What actually works

Start adjusting before you leave

For east-bound flights (the harder direction, because you’re moving against the earth’s rotation and shortening your day), start shifting your sleep one to two hours earlier in the two days before you fly. For west-bound flights (easier, longer day, most people adjust faster), shift slightly later. Even a one-hour pre-adjustment makes a difference when you land.

This is low-effort and most people skip it. Don’t skip it.

Light is the master lever

Your circadian clock is reset by light, specifically by morning light hitting your eyes. This is a faster lever than sleep alone.

When you arrive: if it’s daytime at your destination, get outside. Actual outdoor light, not indoor light through a window. Sit in a park, walk, eat outside. Even 20-30 minutes of morning light exposure on arrival day does measurable work.

If it’s nighttime on arrival and you need to sleep: minimize bright light, especially blue light from screens, for 1-2 hours before bed. Your phone is actively telling your brain it’s daytime. Same with the hotel TV. Dim screens or use night mode from the moment you’re in your room.

Some people use a light therapy lamp (a small portable one travels reasonably well) for morning light on winter arrivals when you land somewhere dark. This is not placebo. The light-melatonin mechanism is well-documented. Whether it’s worth the bag space is a personal call.

Get on local time immediately

Set your watch to destination time as soon as you board the plane. Start thinking in the new time zone. Don’t calculate “what time is it at home.” This sounds psychological rather than physiological, but it matters because it changes when you start targeting sleep and meals.

On the plane, sleep when it’s nighttime at your destination. Not when you’re tired. Not because the cabin lights dimmed. When it’s night WHERE YOU’RE GOING.

Yes, this is hard. A sleep mask and earplugs help a lot. On long-haul eastbound flights, sometimes this means staying awake for the first part of the journey and sleeping the second part, which is uncomfortable. The discomfort is the price of landing functional.

The melatonin question

Melatonin is not a sleeping pill. It’s a biological signal that tells your body it’s dark and it should start winding down. Small doses (0.5mg to 1mg, NOT the 5-10mg doses common in American pharmacies, which are pharmacological doses many times higher than what your body naturally produces) taken at local bedtime for the first few nights of a trip do help shift the circadian clock.

Note: melatonin is prescription-only in several countries, including the UK and most of Europe, Japan, and Australia. It’s available over the counter in the US, Canada, and some other countries. If you rely on it, carry it from home rather than assuming you can buy it at your destination.

Eat on local time

Your gut has its own clock. Meal timing sends time-of-day signals to your body, separate from the light system. Eating breakfast when it’s breakfast time locally, lunch when it’s local lunch, and dinner when it’s local dinner accelerates adjustment. Eating at random times or continuing your home schedule in your head slows it down.

The practical implication: if you land at 6am destination time and aren’t hungry, eat something light anyway. If you land at 10pm and you’re hungry because your body thinks it’s noon, eat something light and go to sleep.

Avoid large meals in the middle of your biological night. Your digestive system is in rest mode and the result is neither comfortable nor conducive to adjustment.

Stay hydrated

Plane cabins are pressurized to roughly 8,000 feet altitude with humidity around 10-20% (for context, the Sahara Desert is roughly 25% humidity). Dehydration amplifies every jet lag symptom. It makes fatigue worse, makes headaches worse, impairs cognitive function.

Drink water consistently throughout the flight. Not alcohol, which dehydrates further and disrupts sleep architecture even when it makes you feel sleepy. Not excessive coffee, which dehydrates and pushes cortisol up at the wrong times. Water. And if the flight is over 8 hours, electrolytes. Bring a small rehydration sachet or a packet of electrolyte tablets.

The first day strategy

The single most effective thing you can do: stay awake until local bedtime on arrival day, even if you’re exhausted. Even if the bed looks incredible. Even if you’ve had 4 hours of broken sleep on the plane and you would very much like to disappear into a pillow.

This one commitment resets the sleep clock faster than almost anything else, because it means you accumulate enough sleep pressure to actually sleep the full night at the right local time. The people who take the “just a quick nap” on arrival day often wake up three hours later at 7pm, can’t sleep until 3am, and spend the next week struggling.

If you absolutely cannot stay awake: set an alarm for 90 minutes maximum. 90 minutes is one sleep cycle. You’ll feel better after one full cycle than after an incomplete one, and you can stay awake until bedtime after.

East vs west: why direction matters

Flying east is harder. You’re shortening your day, which means you need to fall asleep earlier than your body wants to and wake up earlier than it wants to. Flying west lengthens your day and most people find it more natural to stay awake later and sleep in.

The rule of thumb most frequent flyers use: going west, you can probably manage with behavioral adjustment (local time, light exposure, hydration). Going east more than 6 time zones, consider adding melatonin at local bedtime for the first 2-3 nights.

For extreme eastbound shifts (North America to Japan or Australia, for example, 14-18 hours), some travelers use a two-stop strategy: add a stopover of 1-2 days in a midway time zone. This is more time but significantly less physical cost, and it means you’re functional from day one at your destination rather than spending the first three days rebuilding.

The things that don’t work (as advertised)

First-class seats. Better sleep in better seats does reduce travel fatigue, but fatigue and jet lag are different problems. A well-rested person is still jet-lagged. The science of sleep stage disruption from time-zone crossing is not solved by a lie-flat bed, though it absolutely makes the journey more pleasant.

Sleeping through the entire flight. Often the wrong strategy for east-bound travel, where you need to sleep at the right local time, not the random time you board.

Immediately resuming normal life on arrival. Working a full day on arrival day when you’ve crossed 10 time zones is aspirational to the point of self-delusion for most people. Build in a transition day if the trip matters.

Drinking alcohol to “help you sleep” on the plane. Alcohol suppresses REM sleep (the restorative stage), dehydrates, and disrupts sleep architecture. You’ll feel like you slept but you won’t have gotten proper rest. This is a beloved myth that keeps airlines profitable.

Those apps that tell you to not eat for 16 hours before a flight. The “Argonne diet” and variations of it have weak evidence and are largely impractical. The meal-timing approach above (eating on local time starting on the plane) is better supported and less miserable.

The long-haul reality

I cross large time zones roughly every 4-6 weeks. I’ve gotten reasonably good at adjustment, but “reasonably good” still means the first two days in a new time zone aren’t peak performance days. I know this, I plan for them, and I don’t schedule my most important or demanding activities for days one and two.

Jet lag is not fully solvable. It’s manageable. The gap between “arrived in Tokyo and spent two days as a philosophical zombie” and “arrived slightly tired but functional from day one” is entirely about these strategies applied consistently. Not one of them, all of them together.

The corn soup in the hotel vending machine was actually quite good, for the record. But I’d rather have eaten a normal dinner at a normal hour like a person with a circadian rhythm.

Get the melatonin, drink the water, stay awake until 10pm local time. You’ll thank yourself.