Jet Lag Recovery Calculator
Estimate how many days your body needs to adjust to jet lag after a trip, using the rule of thumb of about one day per time zone crossed.
Dias estimados
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Estimating jet lag recovery
The common rule of thumb gives you one day of recovery per time zone crossed. Fly 8 hours east (São Paulo to Lisbon, say) and your circadian rhythm needs roughly 8 days to settle back into place. Eastward travel is harder than going west. The reason is that advancing your biological clock is trickier than delaying it, and most of us find it easier to stay up later (west) than to wake up earlier (east). A few things help. Start shifting your sleep by an hour a day in the days before you leave, chase morning sunlight once you land (it's the strongest zeitgeber), take melatonin 0.5–3 mg about 2 hours before your local bedtime (in Brazil this is regulated by ANVISA RDC 922/2024, so talk to a doctor), drink plenty of water, and skip the alcohol on the plane.
Applications
Long-haul international trips, athletes competing across time zones (Olympics, World Cup), executives and consultants who practically live on planes, and pilots and cabin crew. The FAA caps flight time and rest periods for exactly this reason: jet lag adds up.
FAQ
Is jet lag worse going east or west? East. Your body delays sleep more readily than it advances it.
Does melatonin really work? The evidence backs low doses (0.5–3 mg) taken near your local bedtime. Going higher won't do more for you and can leave you groggy.
Can I avoid jet lag entirely? Not on trips crossing 3 or more time zones. But adjusting your sleep ahead of time, getting the right light, and using melatonin can roughly halve the recovery.
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The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.