How bad will your jet lag be? Get a severity score, recovery timeline, and personalized tips — before you fly.
Expect significant disruption for several days.
10
hours time difference
ahead at destination
10
days to fully adjust
~1 day per 1hr eastward
Quick routes
Adjust your sleep schedule 2-3 days before departure — shift bedtime earlier (eastward) or later (westward) by 30-60 min per day.
Avoid alcohol and caffeine for 24 hours before and during your flight. Both worsen dehydration and disrupt sleep cycles.
When you arrive, immediately sync to local time. If it's daytime at your destination, stay awake. Avoid napping longer than 20 min.
Get bright light exposure in the morning (for eastward travel) or evening (westward) — light is your body clock's most powerful reset trigger.
Consider melatonin (0.5-5mg) at your new destination's bedtime for the first 3-4 nights. Take it 30 min before target sleep time.
On long-haul flights: set your watch to destination time immediately at takeoff. Sleep when it's night at your destination, stay awake otherwise.
Your body runs on a ~24-hour internal clock (circadian rhythm) governed by the suprachiasmatic nucleus in your brain. It controls sleep, hormone release, body temperature, and digestion timing.
Bright light, especially blue-spectrum morning light, is the most powerful signal to your clock. This is why strategic light exposure — or avoiding it — is the key evidence-based recovery tool.
Your natural circadian cycle is slightly longer than 24 hours (~24.2h). Extending the day (westward travel) is easier than compressing it (eastward). This is why LA→Tokyo (eastward) is far harder than Tokyo→LA.
You've got the jet lag sorted. Now budget your trip, pack right, and check visa requirements — all free tools.