Jet Lag: Tips to Reset Your Body Clock

Jet lag is your body clock arriving at a destination several hours before the rest of you catches up. The result is the familiar cocktail of daytime sleepiness, midnight alertness and a foggy head that makes the first few days of a trip feel wasted. The good news is that you can influence how quickly your clock resets, starting before you even board the plane.

What causes jet lag

Your internal clock runs on its own rhythm and relies on light, meals and activity to stay synchronised with local time. When you cross several time zones quickly, the world changes faster than the clock can follow, so your body keeps following home time. Travelling east usually feels harder than travelling west, because shifting your day earlier is harder for most people than shifting it later, a point our overview of circadian rhythm disorders explains in more depth.

Before you travel

• On the two or three days before an eastward trip, move your bedtime and morning light exposure about an hour earlier each day
• Before a westward trip, do the opposite: stay up and get up a little later
• Book flights that arrive in the late afternoon or evening so you can sleep in line with local night
• If you can, pick the same side of the plane as your destination's evening to avoid bright morning sun on approach

In the air

The cabin makes a poor laboratory for your clock. Set your watch to destination time as soon as you board and live by it from then on. Eat meals at times that match the destination, keep water flowing rather than relying on alcohol or excessive caffeine, and use a mask or window shade to match light to your target schedule. Moving around every couple of hours also helps circulation and keeps you from arriving stiff and sleepier than necessary.

On arrival

Once you land, local daylight is your strongest tool. Spend time outdoors in the morning of your first days, keep meals on local time, and avoid long afternoon naps that would reset you to home hours. A short nap of twenty minutes can take the edge off, but anything longer risks anchoring you to the wrong schedule. Our article on napping well explains the timing in more detail.

Light at the right time

Light before about mid-afternoon nudges the clock earlier, while light later in the day pushes it later, so use it deliberately. If you travel east and feel alert at local midnight, avoid bright screens and keep the room dark. If you travel west and find yourself sleepy at local early evening, get outside for a walk rather than giving in to bed.

How long does it last

As a rough guide, the body adapts about one time zone per day, so a five-hour jump typically takes around five days to fully settle. Most people feel the worst on day two and improve steadily from there. The reset also depends on how consistent your light and sleep are, and the fundamentals in our sleep hygiene guide speed the process along.

Understanding how cycles rebuild across the night, covered in our guide to sleep cycle stages, makes it easier to plan your recovery. With a little preparation and disciplined light exposure, most jet lag can be kept to a day or two rather than a lost week.