Jet lag is not tiredness. You can be jet lagged and wide awake, which is the version that wakes you at three in the morning feeling ready to go for a run. What you are experiencing is a disagreement: your internal clock is still keeping time somewhere you no longer are, and it is running your temperature, your appetite and your alertness on that old schedule.
That matters because it tells you which interventions can possibly work. Anything that moves the clock helps. Anything that only makes you more comfortable is worth doing for its own sake, but it will not shorten the adjustment by a single hour. Most popular advice about long flights is the second kind sold as the first.
Light is the lever, and direction decides how you use it
The strongest signal your body clock takes is light. Not sleep, not meals, not willpower — light hitting your eyes, and the time of day at which it does. Everything else is a supporting cue.
Direction changes what you should do with that. Flying east asks your body to do the harder thing: fall asleep before it is ready. Flying west asks it to stay up later, which is something most people's bodies are quietly willing to do anyway. That asymmetry is why the same six-hour shift feels so different depending on which way you crossed it.
In practice, going east, chase the morning. Get outside early at your destination, and dim things down in the evening rather than sitting under bright light until midnight. Going west, do the reverse: get evening light, stay out at dusk, and don't take an early-morning walk into direct sun on the first day, which pulls you back the way you came.
Anything that moves your body clock helps. Anything that only makes you more comfortable is worth doing for its own sake, but it will not shorten the adjustment by an hour.
Start living in the destination before you land
Change the time on your watch at the gate, not on arrival, and start making decisions in that number instead of converting. It sounds like a gimmick. It is the difference between choosing to sleep because it is eleven at night where you are going and choosing to sleep because you are bored.
From there, one rule covers most of the flight: sleep if it is night where you are going, stay awake if it is not. A twelve-hour flight that lands in the evening is a flight you should mostly stay awake on, however tempting the dark cabin is, because arriving tired and going to bed at a normal local hour is the fastest route through this. A flight that lands at breakfast is one to sleep on, even badly.
The things that make the flight itself survivable
None of this shifts the clock. It is still worth doing, because arriving stiff, dehydrated and irritable makes the first day worse than it needs to be.
- Cabin air is extremely dry. Drink more water than you feel like, and take a small bottle through security empty and fill it after, so you are not waiting on a cart.
- Alcohol is a poor sleeping aid in the air for the same reason it is on the ground: it gets you under faster and fragments what follows. One drink is fine. Using it as the plan is not.
- Coffee lingers in your system for many hours. The cup that seems harmless on the descent is the reason you are staring at a hotel ceiling later.
- Get up and move every couple of hours, and pick an aisle seat if that is going to be you. Sitting still for a very long stretch is the part of long-haul flying with an actual medical downside — if you have any risk factors at all, ask your doctor about it before a long trip rather than reading about it afterward.
- Take the window if you intend to sleep. You control the shade and nobody needs to climb over you. Take the aisle if you don't.
- Bring a real eye mask and earplugs rather than relying on what's in the seat pocket. They cost almost nothing and they are the two most effective comfort items on the aircraft.
Meals, and the drugs question
Eating on the destination's schedule is a genuine secondary cue, and it is free. That means taking the meal that lines up with local mealtimes and skipping the one that doesn't, regardless of what the cabin crew are doing. It also means resisting a large meal at what your body considers dinner and your destination considers the middle of the night.
People will recommend melatonin, sleeping tablets, or various prescription options. This is genuinely a conversation to have with a pharmacist or doctor rather than with an article, for two reasons. The timing of anything you take matters enormously and depends on which direction you flew. And its legal status varies: something sold on a supermarket shelf in one country is prescription-only in the next and restricted at the border of a third. Check the rules for where you are going before you pack anything, including things you take routinely.
Plan the first two days like you know you'll be impaired
- Do not schedule the thing that matters for the first morning. If you have any say over it, put the important meeting on day two or three.
- Get outside within an hour or two of waking on the first day, whatever the weather. Overcast daylight is still far brighter than any room.
- If you must nap, keep it short and take it early in the afternoon. A long nap at five o'clock will cost you the night.
- Eat at local mealtimes from the first meal, even if you are not hungry at any of them.
- Go to bed at a plausible local hour rather than the moment you feel able to. The first night is usually broken regardless; the second is the one that tells you whether the plan is working.
When it isn't worth adjusting at all
For a short trip across many time zones — two or three nights — you may be better off not trying. By the time you have shifted, you are flying home and doing it again in the harder direction. Staying loosely on home time and scheduling what you can inside the hours that overlap is often less punishing than a half-completed adjustment in both directions.
For anything longer, commit on the first day. The people who struggle for a week are almost always the ones who spent the first two days negotiating — a late nap here, a dark room until noon there — and never gave their clock a consistent signal to follow.