What are the symptoms of jet lag?

Jet lag happens when your body clock is out of step with the time at your destination. You may wake earlier or later than planned, feel tired during the day, or struggle to stay alert during work or travel. Some people notice irritability, reduced concentration, a mild headache, changes in appetite or unsettled digestion. Symptoms may feel stronger after crossing several time zones and can vary with travel direction, sleep loss and the demands of the trip. Daytime sleepiness and difficulty sleeping can also occur for reasons other than jet lag.

Use the local schedule soon after arrival: seek daylight during the day, keep meals close to local mealtimes and reserve the bed for sleep. Keep evening light low if you are trying to sleep, and make the room quiet and cool. Drink fluids, avoid driving when you feel drowsy, and keep any nap brief enough that it does not replace nighttime sleep. A travel health consultation can help if you have frequent long-distance trips, take regular medicines or have a sleep condition.

Arrange medical advice if sleep disruption or daytime sleepiness continues after you have had time to adjust, repeatedly affects work or driving, or is accompanied by severe headache, confusion, fainting, chest symptoms or marked mood change. Seek urgent help for sudden neurological symptoms or difficulty staying awake safely. A clinician can consider insomnia, another sleep problem or a separate cause rather than assuming every post-travel symptom is jet lag.

Could another sleep problem explain these symptoms? Which changes to light, sleep and meals fit my itinerary? Are any of my medicines affecting alertness or sleep? When is it safe for me to drive or return to demanding work?