Jet Zzz is a free, browser-based jet lag planner. Follow these steps to build a personalized day-by-day adjustment schedule for any flight.
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.
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.
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.
Yes. Jet Zzz is completely free to use in your browser. No account is required.