Jet lag happens when fast travel across time zones desynchronizes your internal circadian clock from the local day-night cycle, leading to fatigue, poor sleep, and reduced concentration.

How long does jet lag last?

As a rule of thumb your circadian rhythm shifts roughly one hour per day, so a six-hour time change typically takes several days to fully adjust. Eastward travel is usually harder than westward.

Can a planner actually reduce jet lag?

Yes. A structured plan that times sleep, light exposure, and activity in the days before and after a flight can meaningfully shorten adjustment compared with doing nothing.

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The Best Time to Sleep on a Long-Haul Flight

The Best Time to Sleep on a Long-Haul FlightSleep on the plane should match nighttime in your destination, not your origin. Otherwise the flight just extends your old time zone and the real adjustment starts only after you land.The ruleReset your watch to destination time at boarding. Sleep when it is night at the destination, even if it means staying awake the first few hours. Stay awake when it is day there, even if you are tired.Eastward exampleNew York to London is a five-hour eastward shift. Sleep right after the meal service (around 02:00 London time), aim for four to five hours, get bright light on arrival.Westward exampleLondon to Los Angeles is an eight-hour westward shift. Stay awake for the whole flight if possible — it is daytime in LA. A short nap before landing is fine.Practical tipsEarplugs and an eye mask outperform any sleep aid. Skip alcohol. Hydrate. If you cannot fall asleep within 30 minutes, do not force it — read briefly with low light and try again.