The effects of jet lag: what to know

Your internal body clock coordinates sleep, alertness, meals and hormone signals. Crossing time zones moves the local schedule faster than that clock can adjust. You may feel awake at night and sleepy during the day, with headache, irritability, poor focus or appetite changes. Jet lag is different from insomnia, although travel-related sleep disruption can resemble it.

Symptoms are shaped by travel direction, the number of time zones crossed, sleep loss and your planned activities. They generally ease as your body clock aligns with local light and routine.

Adopt the destination schedule for meals and sleep, seek daylight at an appropriate local time, and keep evening light low when preparing for bed. Drink water, limit alcohol, and use caffeine thoughtfully rather than late in the day. A short nap may help alertness, but long daytime sleep can delay adjustment. For repeated or severe disruption, ask about insomnia management or a travel health consultation before using sleep medicines or melatonin.

Seek medical advice if sleep problems persist well after travel, daytime sleepiness makes driving unsafe, or headaches are severe or unusual. Urgent help is needed for sudden weakness, confusion, fainting, chest pain or severe breathing difficulty; do not assume these symptoms are jet lag.

Ask: When should I seek light exposure at my destination? Is a nap appropriate for my itinerary? Could another sleep condition be present? Are any medicines or supplements unsuitable with my health conditions? How can I stay safe if I feel sleepy while travelling?