Jet lag & time zones — light, sleep, and a simple planner

Time zone & light planner

Pick your usual zone and your destination. Times update in your browser using Intl (no server call). Modern browsers expose a long list of IANA zones via Intl.supportedValuesOf('timeZone'); older ones fall back to a short curated list.

Before the flight

• Shift sleep gently, not drastically. Moving bedtime by 30–60 minutes for a few nights toward destination time can help, especially before eastbound trips. Avoid heroic all-nighters — sleep debt makes adaptation harder.
• Anchor with light. Morning outdoor light pulls the clock earlier; bright evening light delays it. Pair light with your planned direction, but don’t stare at the sun — normal daylight walks are enough.
• Stabilise caffeine and alcohol. Limit caffeine after mid-afternoon before departure; alcohol fragments sleep and dehydrates — both work against you on long hauls.
• Plan the first night. Book a calm arrival window if you can, and know how you’ll get from the airport — stress burns the energy you need to sleep later.
• Cross-check gear. Use our packing checklists, airport day guide, plugs & voltage, and roaming / eSIM guide so logistics don’t steal sleep.

During the flight

• Hydrate steadily. Cabin air is dry; small, frequent water beats chugging once. Moderate alcohol — it worsens dehydration and sleep quality.
• Move every hour or two. Walk the aisle, stretch calves and ankles — reduces stiffness and supports circulation on long segments.
• Align light with destination, roughly. If it’s night at your destination, try dimming your screen and using an eye mask; if it’s day there, light exposure in the cabin can help. Exact timing is individual.
• Melatonin and prescription sleep aids. Only use substances under professional guidance — dose and timing matter, and they interact with other medicines.
• Set watch mentally to destination time early — it helps meal and nap decisions, but listen to your body if you’re exhausted.

After you land

• First day: aim for destination rhythm. If you arrive in the morning, light activity and daylight help; if you land at night, keep lights low and try a normal-length sleep block.
• Short naps. A 20–30 minute nap can rescue you without wiping out night sleep; long afternoon naps often delay adaptation.
• Meals on local time. Regular meal times are a secondary “zeitgeber” that supports your clock alongside light.
• East vs west. Many travellers find eastbound (losing night hours) harder than westbound (stretching the day) — but individuals vary widely.
• Give it several days. One time zone per day is a rough rule of thumb for full adjustment; long trips may need longer.
• Budget and plan the trip in the Travel Planner or the trip cost estimator so money stress doesn’t stack on top of fatigue.