Jet lag happens when you cross time zones faster than your body clock can adjust. The fastest way to beat it is to use light at the right time of day: get bright morning light after flying east, and evening light after flying west. Combine that with shifting your sleep schedule a little before you leave, switching to local time as soon as you arrive, and keeping caffeine and alcohol in check. For remote workers, it also helps to plan a lighter workload for the first few days in a new time zone.
What causes jet lag
Your body runs on a roughly 24-hour internal clock, the circadian rhythm, which controls when you feel sleepy and alert. Light is its main signal. The hormone melatonin, which helps you fall asleep, is released in darkness and suppressed by light. When you land in a new time zone, your internal clock is still running on home time, so you feel sleepy at midday and wide awake at night until it catches up.
According to the CDC Yellow Book, common symptoms include poor sleep, daytime sleepiness, difficulty concentrating, general malaise and stomach upset. It is common: one survey cited by the CDC found 68% of international business travelers regularly experienced negative symptoms.
Why flying east is harder
Your internal clock naturally runs slightly longer than 24 hours, so it is easier to stay up later (as you do after flying west) than to fall asleep earlier (after flying east). As a rough guide from the CDC Yellow Book, people adjust by about 1.5 hours per day after westward travel and about 1 hour per day after eastward travel.
| Example trip | Time change | Rough time to fully adjust |
|---|---|---|
| New York to Lisbon | 5 hours east | About 5 days |
| Lisbon to New York | 5 hours west | About 3 to 4 days |
| London to Bangkok | 6 to 7 hours east | About a week |
Everyone is different, and the right habits can speed this up. For trips shorter than about two days, the CDC suggests staying on your home time zone rather than trying to adapt.
Before you fly
- Shift your sleep gradually. For two or three days before the trip, move your bedtime and wake time about an hour per day toward your destination: earlier for eastward trips, later for westward ones.
- Arrive rested. Sleep loss before and during travel makes jet lag worse, so avoid a late night of packing.
- Choose your flight thoughtfully. Arriving in the late afternoon or early evening often makes it easier to stay up until a normal local bedtime.
- Clear your work calendar. Avoid scheduling important calls or deadlines for the first day or two after a big time change.
During the flight
- Switch your watch to destination time when you board, and try to sleep or stay awake according to that time.
- Drink water and limit alcohol and caffeine, which the CDC notes can worsen dehydration and disrupt sleep.
- Bring an eye mask and earplugs to make sleeping on the plane easier.
- Move around when it is safe to, and stretch in your seat on long flights.
After you arrive: use light to reset your clock
Light is the most powerful tool you have. The CDC explains that bright morning light tends to shift your body clock earlier, while evening light shifts it later.
| After flying east | After flying west | |
|---|---|---|
| Seek light | In the morning | In the late afternoon and evening |
| Avoid bright light | In the evening (dim screens, wear sunglasses outside late in the day) | Early in the morning |
| Sleep | Go to bed at local bedtime even if you are not tired | Stay up until local bedtime; avoid dozing off early |
For very large time changes, the ideal timing of light can shift during the first few days. Jet lag apps and calculators can build a personalized plan from your flight details.
Naps, caffeine and meals
- Keep naps short, around 20 to 30 minutes, and take them earlier in the day so they do not steal from night-time sleep.
- Use caffeine strategically in the morning and early afternoon to stay alert, and stop well before bedtime.
- Eat on local time from your first day, keeping dinner light so it does not disturb sleep.
- Get moving outside. A walk in daylight combines light exposure and activity. See how to stay fit while traveling.
What about melatonin?
Melatonin supplements are widely used for jet lag, particularly after eastward flights. The CDC’s guidance describes taking it before bedtime at your destination, and advises against high doses (above 5 mg), which can leave excess melatonin in your system at the wrong time of day. Timing matters: taken at the wrong time, melatonin can shift your clock in the wrong direction. The CDC also notes there is limited data on how melatonin interacts with other medications.
Rules also differ by country. Melatonin is sold over the counter in some places, such as the US, but requires a prescription in others, including the UK. Speak to a doctor or pharmacist before using it, especially if you take other medication, are pregnant, or have a health condition. For more on supplements in general, see our guide to supplements for travelers.
A jet lag plan for remote workers
- Days before the flight: shift your sleep toward destination time and finish urgent work early.
- Arrival day: no important calls. Get outside at the right time of day for light, eat on local time and go to bed at local bedtime.
- Days 2 and 3: focus on routine tasks rather than deep, creative work. Schedule calls at the times you feel most alert.
- By the end of week one: return to your normal schedule. Our work-life balance guide has sample schedules for working across time zones.
The best cure for jet lag is simply flying long-haul less often. Staying in each region for months at a time, as described in our slow travel guide, means fewer big time changes and fewer lost workdays.
Frequently asked questions
How long does jet lag last?
As a rough guide, people adjust about one hour per day after flying east and about an hour and a half per day after flying west. A five-hour eastward change can take around five days to fully resolve.
What is the fastest way to get over jet lag?
Switch to local time immediately and use light strategically: morning light after flying east, evening light after flying west. Add good sleep habits, sensible caffeine use and daytime activity.
Is jet lag worse flying east or west?
Usually east. Your body clock finds it easier to shift later than earlier, so adjusting to an earlier bedtime after an eastward flight takes longer.
Last reviewed: September 2026. This article is general information, not medical advice. Talk to a doctor before using sleep aids or supplements.
