How to Beat Jet Lag: What Actually Works
Forget the myths. The science points to three levers: timed light exposure, pre-shifted sleep, and strategic melatonin and caffeine. Here's the playbook for both directions.
Key takeaways
- Three levers actually work: timed light exposure, pre-shifted sleep, and strategic melatonin/caffeine.
- Eastward (US → Europe): seek morning light. Westward (US → Asia): seek evening light.
- Expect about one day of adjustment per time zone eastward, half a day per zone westward — less if you prepare.
- Start 3 days out: shift bedtime and wake time one hour per day toward the destination.
Why eastward is worse
Your internal clock runs a little longer than 24 hours, so staying up later (westward) feels natural while falling asleep earlier (eastward) fights your biology. Rule of thumb: one day of adjustment per time zone eastward, half a day per zone westward — less if you prepare.
The 4-part playbook
1. Shift sleep before you fly (3 days out)
| Direction | Shift | How |
|---|---|---|
| Eastward | Bed/wake 1 hour earlier daily | Morning bright light on waking |
| Westward | Bed/wake 1 hour later daily | Bright light in the evening |
Three days of shifting buys you three time zones of adjustment before you board.
2. Time your light on arrival
- Eastward: get outside in the morning; wear sunglasses in the late afternoon/evening for the first 2 days
- Westward: seek late-afternoon/evening light; avoid bright morning light
- Overcast daylight still works — it's far brighter than indoor light
3. Use melatonin as a timing signal
Low dose (0.5–3 mg) at the destination bedtime for 3–4 evenings. It's a clock-setting signal, not a sedative — higher doses don't work better and can leave you groggy.
4. Time your caffeine
Caffeine in the destination morning/early afternoon boosts alertness when you need it. Cut it off 8+ hours before destination bedtime — it has a 5–6 hour half-life and will wreck the sleep you're trying to build.
On the plane
- Set your watch to destination time at boarding — eat, sleep, and caffeinate on that clock
- Sleep when it's night there, stay awake when it's day there (eye mask + earplugs help enormously)
- Hydrate aggressively — cabin air is ~10–20% humidity; dehydration amplifies fatigue
- Move every few hours — walk the aisle; it helps circulation and sleep quality later
What doesn't work
- Staying up all night before the flight — you arrive exhausted and misaligned
- Alcohol as a sleep aid — fragments sleep architecture and dehydrates
- Sleeping pills for timing — they sedate without shifting your clock (fine for comfort, useless for jet lag)
- Napping "just 20 minutes" at 4pm — it will become 3 hours and destroy that night's sleep
Plan around the time zones
Compare your home and destination zones to schedule calls — and sleep — at sane hours.
Open the Time Zone PlannerFrequently asked questions
How long does jet lag last?
About a day per time zone eastward, half a day per zone westward — 3–5 days for most long-haul trips with good light timing.
Does melatonin really help jet lag?
Modestly, yes — as a timing signal at destination bedtime, not as a sleeping pill. Low doses work best.
Should I nap on arrival day?
If you must, keep it under 30 minutes and before 3pm local time. Better: stay up until a reasonable local bedtime.
Does flying east or west cause worse jet lag?
East is worse for most people — advancing your clock fights your natural rhythm.
Do jet lag apps work?
Apps that schedule light exposure and sleep (like Timeshifter) are built on real circadian science and beat guessing.
General health information, not medical advice. Consult a doctor about melatonin or sleep aids if you have health conditions or take medication.