1. Why jet lag happens
Jet lag is a temporary sleep problem that usually appears when you cross three or more time zones quickly. The body's internal clock still follows home time, so it is out of sync with the destination's day and night.
Symptoms include trouble sleeping, daytime fatigue, poor concentration and digestive discomfort. Most people recover within a few days, roughly one day per time zone crossed.
2. Shift before you fly
If you have a few days before departure, move your sleep time an hour or two towards the destination schedule: go to bed later and wake later when flying west, earlier when flying east.
Small shifts are easier than one big jump. The destination's daylight schedule is the anchor, so plan meals and sleep around it once you board.
3. Use light after arrival
Bright daylight is the strongest signal for the body clock. Get outside at the destination's daytime hours, and dim screens in the evening to help melatonin rise naturally.
When flying east, morning light helps you shift earlier; when flying west, afternoon and evening light helps you shift later. A short walk outdoors usually beats staying in a dark hotel room.
4. Sleep and meals on arrival
Try to stay awake until a normal local bedtime, even if you are tired. A short nap (under 30 minutes) can help, but long daytime sleeps make the first night worse.
Eat according to local meal times and drink water during the flight. Caffeine can help you stay alert until local bedtime, but avoid it late in the local evening.
5. Common mistakes
Common mistakes include sleeping the whole flight and arriving wide awake at night, taking long naps in the afternoon, staying in a dark room during the day, and relying on alcohol to sleep on the plane.
Another is assuming jet lag disappears instantly: plan the first two days loosely and schedule important meetings or driving after you have had a normal night's sleep.
6. Checklist before departure
Before departure: check the time difference and the direction of travel; shift sleep gradually over several days; set devices to destination time on boarding; book an arrival that leaves you time to see daylight; and avoid a full day of meetings on day one.