How to Beat Jet Lag
Travel
Jet lag is the groggy, out-of-sync feeling you get after flying across several time zones. It happens because your body's internal clock is still running on the time zone you left, while the sun, your meals and everyone around you have moved on. The good news is that jet lag is largely predictable — and with the right light, sleep and meal timing you can shorten it from a week to just a day or two.
- Jet lag comes from a mismatch between your circadian rhythm and the local clock at your destination.
- Expect roughly one day of recovery per time zone crossed if you do nothing to adjust.
- Light is the most powerful lever — seeking or avoiding it at the right time resets your clock fastest.
- Flying east (losing hours) is usually harder than flying west (gaining hours).
- Shift your schedule a little before you fly, then switch to destination time the moment you board.
What Causes Jet Lag?
Your body runs on an internal 24-hour cycle called the circadian rhythm, controlled by a small region of the brain that takes its strongest cue from daylight. This clock governs when you feel sleepy, when you feel alert, your body temperature, digestion and the release of hormones such as melatonin and cortisol. When you fly quickly across several time zones, your internal clock stays on home time while the world around you is on a different schedule. Jet lag is the period of discomfort while the two slowly realign.
Because the clock resets only about an hour per day on its own, a long-haul trip can leave you misaligned for the better part of a week. The symptoms are familiar: daytime fatigue, trouble falling or staying asleep, poor concentration, irritability, headaches and an unsettled stomach.
Why Direction Matters: East vs West
Jet lag is not symmetrical. For most people, flying west is easier than flying east, and the reason is simple: the human body clock naturally runs slightly longer than 24 hours, so it finds it easier to stretch the day (stay up later) than to shorten it (go to sleep earlier).
| Direction | What your body must do | Difficulty |
|---|---|---|
| Flying west (e.g. London → New York) | Stay up later, delay the clock | Easier |
| Flying east (e.g. New York → London) | Sleep earlier, advance the clock | Harder |
| North–south only (e.g. London → Cape Town) | Little or no clock shift | Minimal jet lag |
Travelling mainly north or south — even on a very long flight — crosses few or no time zones, so you may feel travel-tired but not truly jet-lagged. To see how many zones a route actually crosses, compare the two cities on this site.
Before You Fly: Shift Your Clock Early
The single best thing you can do begins a few days before departure. Nudge your sleep and meal times toward your destination by 30–60 minutes a day:
- Flying east? Go to bed and wake up earlier each day, and get bright light in the morning.
- Flying west? Go to bed and wake up later each day, and seek light in the evening.
- Arrive well rested, not sleep-deprived — starting a trip exhausted makes jet lag worse, not better.
- Work out the time difference in advance so you know what local time it will be when you land.
Even shifting your clock by two or three hours before departure can take a meaningful bite out of the adjustment you face on arrival. For a deeper routine, see Best Sleep Strategies Before Long Flights.
Use Light to Reset Your Body Clock
Light is by far the most powerful tool for beating jet lag, because it is the main signal your brain uses to set its clock. The trick is to get bright light at the right time and to avoid it at the wrong time. As a general rule:
| Direction of travel | Seek light | Avoid light |
|---|---|---|
| Travelling east | Morning light at your destination | Late-evening light (wear sunglasses, dim screens) |
| Travelling west | Afternoon and early-evening light | Early-morning light for the first day or two |
Daylight is far stronger than indoor lighting, so getting outside for a walk is the most effective option. At night, keep lights low and put screens away an hour before bed, since bright blue light in the evening tells your brain to stay awake.
On the Plane
The flight itself is where your adjustment really begins. The moment you board, set your watch and phone to your destination's time and start living on it mentally:
- Sleep on the plane only if it is night-time at your destination. An eye mask, earplugs or noise-cancelling headphones and a neck pillow help.
- Stay awake if it will be daytime where you land, even if you are tired — read, watch films or walk the aisle.
- Drink plenty of water. Cabin air is very dry, and dehydration makes you feel worse and amplifies jet-lag symptoms.
- Go easy on alcohol and heavy meals, which disrupt sleep and digestion at altitude.
- Move regularly — stretch and walk every couple of hours to stay comfortable and keep your circulation going.
After You Arrive
Your goal on arrival is to lock onto local time as quickly as possible and resist the pull of your old schedule:
- Adopt local meal and sleep times immediately, even if your body protests.
- Get outside in daylight at the times shown in the light table above — it is the fastest way to reset your clock.
- Limit naps to 20–30 minutes, and not too late in the day, or you will struggle to sleep at night.
- If you land in the morning, try to stay up until a normal local bedtime rather than crashing on arrival.
- Be patient with yourself. A useful rule of thumb is one day of recovery for each time zone crossed, so plan lighter activities for the first day or two.
Food, Caffeine and Melatonin
A few smaller levers can help nudge your clock and manage symptoms:
- Caffeine can keep you alert during destination daytime, but stop in the early afternoon so it does not sabotage your first night's sleep.
- Meal timing is itself a clock signal. Eating at local mealtimes, rather than when your home stomach expects food, helps your body adjust.
- Melatonin is a hormone your body releases at night, and a low-dose supplement taken near your destination bedtime can help some travellers fall asleep on the new schedule. Rules and availability vary by country, so check with a pharmacist or doctor first.
- Stay hydrated and keep meals light for the first day — your digestion is jet-lagged too.
Should You Even Bother Adjusting?
For a short trip of just one or two days, it can be smarter not to fully reset your clock. If you are crossing only a few zones and heading home quickly, staying close to your home schedule — scheduling meetings and meals at times that suit your body — can leave you fresher than a half-finished adjustment in both directions. For longer stays, commit fully to local time from day one.
Frequently Asked Questions
How long does jet lag last?
Without any countermeasures, expect roughly one day of recovery for each time zone you crossed. Good light, sleep and meal timing can cut that significantly, often to a day or two even after a long-haul trip.
Is flying east or west worse for jet lag?
Flying east is usually harder, because it forces your body to fall asleep earlier than it wants to. Flying west, where you simply stay up later, tends to feel easier.
Does melatonin actually help?
For many travellers a low dose taken near the destination bedtime helps with falling asleep on the new schedule, though results vary from person to person. Check local rules and speak to a pharmacist or doctor before using it.
How do I know how many time zones I am crossing?
Compare your departure and arrival cities and look at the difference in their UTC offsets. Learn how those offsets work in How Time Zones Work Around the World.