Beating jet lag

Why jet lag happens, why flying east feels worse, and practical steps to help your body clock catch up faster.

By timenow.click · Updated 19 October 2026 · 4 min read

This guide is general information, not medical advice. If you have a health condition or take regular medicine, ask a doctor or pharmacist before you travel.

Jet lag is what happens when you arrive somewhere faster than your body clock can follow. Your watch says it's morning, but your body still thinks it's the middle of the night. The result can be poor sleep, tiredness during the day, trouble concentrating, an upset stomach and a general feeling of being out of sorts. The good news is that it is temporary, and there is a lot you can do to shorten it.

Why jet lag happens

Inside your brain is a master clock that runs on a cycle of roughly 24 hours. It controls when you feel sleepy and alert, and influences hunger, body temperature and hormone levels. The clock is kept in time mainly by light, especially daylight, along with signals such as meals, activity and social routine.

When you cross several time zones quickly, those outside signals suddenly shift but your internal clock doesn't. It can only move by a limited amount each day, so for a while your body and the local clock disagree. A common rule of thumb is that it takes about a day to adjust for each time zone crossed, although people vary a lot, and the tips below can speed things up.

Why flying east is usually harder

Most people find flying east harder than flying west. For most people the body clock naturally runs slightly longer than 24 hours, so it is easier to stretch the day, staying up later, than to shorten it by going to bed earlier. Flying west from London to New York means a long day and a late night, which most people can manage. Flying east from New York to London means trying to fall asleep when your body thinks it is early evening.

Before you fly

• Shift your sleep a little in advance. For a few days before an eastward trip, go to bed and get up an hour earlier each day. Before a westward trip, go to bed and get up an hour later. Even a partial shift helps.
• Start rested. Arriving already short of sleep makes jet lag much worse. Avoid a late night of packing before an early flight.
• Choose your flight times with care. Where you can, pick a flight that arrives in the afternoon or early evening, so you only need to stay awake for a few hours before a normal local bedtime.
• Plan any medicines. If you take medicine at set times, such as insulin or a contraceptive pill, ask a doctor or pharmacist how to adjust the timing across time zones before you travel.

On the plane

• Switch to destination time. Set your watch or phone to the local time where you are going as soon as you board, and try to eat and sleep according to that time.
• Sleep if it is night at your destination. An eye mask, earplugs or noise-cancelling headphones make it easier. If it's daytime there, try to stay awake.
• Drink water, and go easy on alcohol and caffeine. Cabin air is dry. Alcohol and caffeine both disturb sleep, and their effects can feel stronger when you are already tired.
• Move around. Stretching and walking the aisle on long flights helps you feel better on arrival.

After you arrive

Daylight is the most powerful tool you have, but timing matters.

• After flying east, get outside in the morning light. It helps pull your body clock earlier, in line with the new local time.
• After flying west, spend time outdoors in the afternoon and early evening. Late daylight helps push your clock later.
• For very big jumps east, of eight time zones or more, very early morning light can work against you for the first day or two, because your body may still think it's evening. Some sleep experts suggest waiting until late morning before seeking bright light at first.
• Eat at local mealtimes. Regular meals at the new times are another signal that helps your body adjust.
• Keep naps short. If you must nap, keep it to about 20 to 30 minutes and avoid sleeping late in the afternoon, so you can still sleep at night.
• Stay up until a normal local bedtime. Going to bed at 7 p.m. on the first night often means waking at 2 a.m.
• Be active. A walk outside combines daylight and exercise, both of which help you feel more alert.

What about melatonin and sleeping pills?

Melatonin is a hormone your body makes in the evening, and taking it as a supplement is a popular jet lag remedy. Rules on it differ: in some countries, such as the US, it is sold over the counter as a supplement, while in others, including the UK, it is only available on prescription. Because the right timing depends on your trip, and because it may not suit everyone, talk to a doctor or pharmacist before trying it. The same applies to sleeping tablets, which can help you sleep but don't move your body clock.

Short trips

If you are only away for a day or two, it may be better not to adjust at all. Try to keep close to your home sleep times and schedule important meetings for the hours when you would normally be awake at home. Use the Compare two places tool to see what time it is at home and at your destination side by side.

When to get advice

Jet lag usually clears up on its own within a few days. If you have a medical condition, are pregnant, take medicine at fixed times, or find that sleep problems continue long after you get home, speak to a doctor or pharmacist for advice that fits your situation.