What should you know about jet lag side effects?

You may feel sleepy or mentally slow during the day while finding it difficult to sleep at the local bedtime. Other effects include tiredness, reduced concentration, irritability, a mild headache, and changes in appetite or bowel habits. These effects can be more noticeable after a long flight, a large time-zone change, or travel that disrupts your usual routine.

Jet lag is different from an infection acquired during travel. Symptoms that continue to worsen, or that do not settle as your sleep pattern adjusts, may have another explanation such as insomnia, dehydration, medication effects, or an unrelated illness.

Use the destination's schedule soon after arrival: eat, sleep and seek daylight at local times. Keep evening light low when you are preparing for bed, and make the bedroom quiet, cool and dark. Drink water, choose light meals if your stomach feels unsettled, and avoid using alcohol to force sleep.

A short daytime nap may help if you are struggling to stay awake, but a long or late nap can make local bedtime harder. Do not drive, swim alone or operate equipment when sleepiness affects your alertness. A clinician or travel-health professional can help you plan light exposure or discuss whether a sleep aid is appropriate for you; do not start one without checking its safety.

Seek urgent help for chest pain, severe breathing difficulty, fainting, new weakness on one side, confusion, or a sudden severe headache. Arrange medical advice if vomiting prevents you from drinking, sleepiness makes ordinary activities unsafe, or symptoms are severe rather than gradually easing. Persistent sleep disruption deserves assessment, especially if you snore loudly, stop breathing during sleep, or take medicines that affect alertness.

Could another condition be contributing to my symptoms? Is my current medicine safe with a sleep aid? How should I time light, caffeine and naps for this trip? What symptoms should prompt urgent assessment?