Jet Lag: Symptoms, Causes and Treatment

Jet lag is a temporary mismatch between your internal body clock and the local time after crossing time zones.

Your body clock helps coordinate sleep, wakefulness, appetite and other daily rhythms. A long journey can place daylight, meals and bedtime at unfamiliar hours, so your usual cues no longer line up with where you are.

Jet lag commonly brings difficulty falling asleep at the desired local bedtime, waking at an inconvenient time, and poor-quality sleep. Daytime sleepiness can make concentration, driving and decision-making harder.

Some people also notice headache, low energy, irritability, stomach upset or a reduced appetite. Symptoms can vary from one trip to another because travel direction, timing and your usual routine all matter.

Crossing several time zones changes the clock time quickly, but the body clock adjusts more gradually. Light exposure is a powerful timing signal, so arriving into daylight or darkness at a new hour can shift the adjustment process.

Travel itself can add to the disruption. Sleeping in a seated position, dehydration, alcohol, unfamiliar food, stress and an overnight itinerary can leave you feeling unwell even while your body clock is resetting.

Longer journeys across time zones tend to create a larger gap between your usual routine and local time. Eastward travel may be difficult for some people because it asks the body clock to shift to an earlier schedule.

Irregular sleep before departure, a packed itinerary, frequent travel and a need to perform demanding tasks soon after arrival can make the effects harder to manage.

A clinician can usually assess jet lag from your recent itinerary, the time zones crossed, sleep timing and symptoms. Keeping a brief record of sleep, naps, caffeine and light exposure can make patterns easier to describe.

Assessment also considers other reasons for disturbed sleep or daytime fatigue, especially when symptoms began without travel, persist well beyond the trip, or interfere substantially with daily life.

Set your watch and daily routine to local time when practical. Daylight, a regular local bedtime, meals at local times and gentle daytime activity can help give your body clock consistent signals. Keep naps short and avoid using them late in the local day.

Use caffeine thoughtfully because it can interfere with sleep if taken close to bedtime. A travel health consultation can help you plan light exposure, sleep timing and medicines around a particular itinerary. Speak with a clinician before using sleep medicines or supplements, particularly during pregnancy or when taking other medicines.

Build in a gentler schedule after arrival when you can. Avoid driving, operating equipment or making high-stakes decisions if you are very sleepy. Drink water regularly, eat simply if your stomach feels unsettled, and let family or work contacts know that your sleep timing is shifting.

In the days before a trip, gradually moving sleep and meals toward the destination schedule may make the transition easier. Choose flights and arrival plans that allow rest, pack any regular medicines in hand luggage, and make a plan for daylight exposure once you land.