How to avoid jet lag: the complete guide
Last reviewed: July 2026
Jet lag happens because your internal clock is still ticking in the old time zone while your surroundings already show a new time. With big time jumps, you can rarely prevent it completely — but with the right strategy, you can shorten it significantly and avoid the worst symptoms. The four levers: preparation, behavior during the flight, light and sleep at your destination.
Prepare before you fly
The biggest mistake is only starting once you've arrived. Shift your sleep schedule gradually toward your destination time one to three days before departure — for eastbound flights, go to bed a bit earlier each evening; for westbound flights, a bit later. Just one hour a day already puts your body a step ahead.
Behave the right way on the plane
Set your watch to the destination time as soon as you board, and eat and sleep accordingly, not by your home time. Drink plenty of water, avoid alcohol, and plan your sleep phases around the destination rhythm. A sleep mask and earplugs help if it's night at your destination while you're flying.
Seek out and avoid light strategically
Light is the strongest cue for your internal clock — but only at the right time. At the wrong time of day, bright light shifts your rhythm in exactly the wrong direction. After eastbound flights, you need light in the morning and should avoid it in the evening; after westbound flights, it's the other way around.
Settle in quickly at your destination
Adjust to the local daily rhythm right away: eat at local mealtimes and stay awake until local bedtime, even if it's hard. A short nap of no more than 20–30 minutes is fine, but longer daytime sleep prolongs jet lag.
FAQ
Can you completely avoid jet lag?
With small time differences of one to two hours, often yes. With big jumps of six or more hours, you usually can't prevent it entirely, but with preparation, light timing and a solid plan you can shorten it significantly.
What helps fastest against jet lag?
The single most effective lever is light at the right time of day, because it shifts your internal clock the most. Combined with adjusted sleep and optionally melatonin, it's the fastest method.
Should I sleep on the day I arrive?
Only briefly. Push through until local bedtime and allow yourself at most a 20-minute nap. Long daytime sleep shifts your clock back and prolongs jet lag.
The science behind it
Flyly's plan is based on the phase-response curve of circadian chronobiology — the same model used in sleep research and space medicine for shift work and time zone changes:
- Lockley & Czeisler — Circadian phase-response curve to light, Harvard Medical School
- NASA Ames Research Center — Circadian rhythm & alertness in aircrew
- Roenneberg et al. — Chronotype & social jetlag, University of Oxford
- Eastman & Burgess — How to travel the world without jet lag, Nature / Sleep Medicine Clinics
