Airplane jet lag: resetting your body clock

It can cause difficulty sleeping at night, daytime sleepiness, reduced concentration, irritability, headache, appetite changes, or digestive upset. The direction and number of time zones crossed, flight schedule, sleep loss, and individual routine all influence the experience.

Light, meals, activity, and sleep normally keep the internal clock aligned with the day. After a long flight, those signals arrive at unfamiliar times. You may feel alert when the destination is asleep or hungry when meals are not scheduled.

Jet lag differs from simple travel fatigue. Sitting for a long period and sleeping poorly can leave anyone tired, while circadian disruption specifically follows a time-zone shift. Both can occur together and may take time to settle as local cues reset the rhythm.

Move meals, activity, and sleep toward destination time. Seek daylight when you need to be awake, dim lights before the intended bedtime, stay hydrated, and keep caffeine away from the hours when you plan to sleep. A short nap may restore alertness, but a long or late nap can delay nighttime sleep.

For a demanding trip, gradually shifting bedtime before departure may help. Avoid driving or safety-sensitive work when very sleepy. Melatonin or a sleep medicine is not suitable for everyone; timing matters, and sedating medicines can worsen impairment or interact with alcohol and other treatments. Discuss them with a clinician or pharmacist.

Seek assessment when sleep disruption or daytime impairment continues beyond the expected travel adjustment, prevents normal functioning, or repeatedly becomes severe. Persistent symptoms may reflect insomnia, sleep apnoea, a mood problem, medication effects, or another sleep disorder rather than jet lag alone.

Get urgent help for chest pain, severe breathlessness, fainting, new confusion, one-sided weakness, or a painful swollen leg after travel. These are not routine features of jet lag. If extreme sleepiness makes driving unsafe, stop driving and arrange another way to travel.

For frequent travel or a tightly scheduled arrival, ask how to time light exposure and sleep for your route, whether melatonin is appropriate, and how existing conditions or regular medicines may affect the plan.