Quick answer: Shift your sleep schedule toward your destination a few days before departure, hydrate on the plane, skip alcohol, and get bright light at the right local time on arrival. Eastward travel is harder than westward because advancing your clock is tougher than delaying it.
Why jet lag happens
Your body runs on a roughly 24-hour circadian rhythm tuned to your home time zone. Flying across several time zones faster than your body can adjust leaves you sleepy or wide awake at the “wrong” local times. Light is the strongest cue for resetting that clock — which is why timing your light exposure is the single most effective lever you have.
Before you fly: shift your clock early
Start adjusting three to four days before departure. The direction you travel decides which way to shift:
- Flying east (e.g. New York → London): go to bed and wake up 30–60 minutes earlier each day.
- Flying west (e.g. London → New York): go to bed and wake up 30–60 minutes later each day.
- Set your watch to destination time as soon as you board, and start eating and sleeping on that schedule.
During the flight
- Drink water regularly — cabin air is very dry and dehydration worsens fatigue.
- Skip alcohol and heavy meals; both disrupt the sleep you do get and deepen dehydration.
- If it’s night at your destination, try to sleep; if it’s daytime there, stay awake and move around.
- Get up and walk periodically to reduce stiffness and travel fatigue.
On arrival: time your light
| Direction | Best light | Light to avoid |
|---|---|---|
| East (need to wake earlier) | Bright morning light | Late-evening light |
| West (need to wake later) | Bright late-afternoon / evening light | Early-morning light |
East vs west: why direction matters
Most people find flying east harder than flying west. Our bodies find it easier to delay the clock (stay up later and sleep in) than to advance it (force an earlier bedtime and earlier wake). Crossing more time zones makes the mismatch worse. A rough rule of thumb is one day of recovery per time zone crossed, often less with good light management.
What doesn’t help much
- Staying on your home-time schedule once you arrive — it delays the reset.
- Using alcohol to fall asleep on the plane — it fragments sleep and worsens jet lag.
- Sleeping pills without medical advice — they can leave you groggy and don’t reset your clock.
- Caffeine late in the destination day — it pushes the clock the wrong way and disrupts the sleep you need.
Frequently asked questions
How long does jet lag last?
Roughly one day per time zone crossed, often less with good light management. Eastward travel usually takes longer.
Does melatonin help?
Some studies suggest melatonin can help shift the clock, especially flying east, but it is not right for everyone. Ask a doctor before using it.
Optional resources
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A last-minute trip to a sunny destination can help you reset your body clock with bright daylight — one way to put jet-lag advice into practice.