About the Jet Lag Plan
Jet lag is not tiredness from travel. It is a body clock still running on the time zone you left, and it moves only when light, darkness and a little melatonin reach it at the right hours. This planner takes your flight and your usual sleep and returns the days before and after it, hour by hour: when to seek bright light, when to avoid it, when a 0.5 mg melatonin dose fits, and when to sleep, in the local time of wherever you are that day.
Every rule comes from one source: Charmane Eastman and Helen Burgess, How to travel the world without jet lag (Sleep Medicine Clinics, 2009). The body-clock low point sits about three hours before your usual wake time; light after it moves the clock earlier and light before it moves it later. The clock shifts about an hour a day once you land, advancing is harder than delaying, and beyond seven zones east it is usually better to go the long way round. Time zones and daylight saving come from your browser’s own time-zone data, for your actual travel dates.
Said plainly: this is a schedule built from published sleep research, not medical advice. The melatonin guidance is timing only; check with a doctor before taking it. Nothing you enter leaves your browser.
A real .ics file with every sleep, light and melatonin block as its own event, in
absolute time — your phone shows each one at the right local hour as you cross time zones.
How to Use the Jet Lag Plan
Choose where you fly from and to, and enter the departure and arrival times exactly as your ticket prints them — each in its own city’s local time. Add your usual bedtime and wake time at home, then decide how you will live after landing. Shift sleep gradually is the approach the research recommends: your sleep moves about an hour a day together with your body clock, so the two never fall out of step. Local hours from day one is what most business trips force; you sleep on the local clock and the plan manages light around your body clock instead. The plan then lists every day, with a 24-hour strip showing when to sleep, when to get bright light, when to avoid it and when a low dose of melatonin fits.
The One Number Behind Every Instruction
Everything hangs on the time your core body temperature bottoms out, the Tmin. It sits about three hours before your usual wake time: 4 am for someone who wakes at 7. It is the sleepiest point of your day and, crucially, the crossover in how light affects the clock. Light in the hours after the Tmin moves the clock earlier; light in the hours before it moves the clock later. After a long eastward flight your Tmin can land at 11 am local time, which is why “get out in the morning sun” can be exactly the wrong advice for the first day or two: sunshine at 9 am would still be before your Tmin, pushing the clock the wrong way. This planner computes the Tmin for every day of the trip and places each light window on the correct side of it.
East, West and the Long Way Round
- Westward flights ask the clock to run later, which it does naturally because the human clock runs slightly longer than 24 hours. Recovery is quicker.
- Eastward flights ask it to run earlier, which is harder. Travellers adapt at around an hour a day, so seven zones east means about a week without preparation.
- Eight or more zones east is where many travellers’ clocks shift the wrong way round anyway. The paper’s guideline is to plan a delay for these trips (16 hours later rather than 8 earlier), and the planner does unless you choose otherwise. It shows how many days each route would take so you can decide.
Why Starting Before You Fly Wins
The biggest gain is made at home. Shifting your sleep an hour a day earlier for three days before an eastward flight, with bright light in the morning and 0.5 mg of melatonin in the afternoon, has been shown to advance the body clock by about an hour a day without jet-lag symptoms. Three days of that turns a seven-hour problem into a four-hour one before you board, and every hour you move at home is an hour you do not spend foggy at your destination. For westward trips the same idea runs the other way: stay up later with bright light in the two hours before bed.
Melatonin: Timing, Not Knockout
Melatonin is a darkness signal, not a sleeping pill. Taken in the afternoon or early evening it moves the body clock earlier; taken in the morning it moves it later. The plan uses only the low 0.5 mg dose, because it shifts the clock as well as larger doses without making you drowsy during the day, and only when the clock needs to move earlier — the paper does not use it for delays. Timing shows up as a single mark on each day’s strip, about 4.5 hours before bedtime on your shifted schedule. In the US melatonin is sold as a supplement and is not FDA-approved for jet lag; ask a doctor before using it.
Related tools: the Sleep Calculator for bedtimes by sleep cycle once you have landed, the Travel Budget Calculator for the rest of the trip, and the Flight Delay Checker before you leave for the airport. Browse every Health & Fitness tool for more.
Not medical advice. This plan applies the timing rules of Eastman & Burgess (2009) to the times you enter; real body clocks vary, and the shift rates are estimates. Melatonin guidance is timing only — check with a doctor before taking it. Anyone flying crew schedules, managing a sleep disorder or taking sedating medication should get individual advice.
Frequently Asked Questions
Why is flying east worse for jet lag than flying west?
Because the human body clock runs slightly longer than 24 hours, so it drifts later on its own and moving it later is easier. Flying west asks the clock to shift later, which it can do by roughly an hour or more a day. Flying east asks it to shift earlier, which is harder: travellers adapt at around an hour a day at best, and after crossing eight or more zones eastward many people end up shifting the long way round.
When should I get sunlight to get over jet lag?
It depends on where your body clock is, not on the local clock. Light after your body temperature low point, which sits around three hours before your usual wake time, moves the clock earlier; light before it moves the clock later. After an eastward flight that low point can land in the middle of the local morning, so morning sun too early can push you the wrong way. That is why this plan gives times in local hours computed from your own sleep.
Does melatonin help jet lag, and when should I take it?
Timing matters more than dose. The research this plan follows uses a low 0.5 mg dose in the afternoon or early evening, about 4.5 hours before bedtime on your shifted schedule, to move the body clock earlier, and does not use it for westward flights. In the US melatonin is a dietary supplement that is not approved by the FDA for jet lag; check with a doctor first, especially if you take other medicines, are pregnant or have a medical condition.
How many days does it take to get over jet lag?
Roughly one day per time zone when the body clock has to move earlier, and a little faster when it moves later, if you manage light well. Without any plan it can take longer, and some travellers barely shift for days when they get light at the wrong times. Starting to shift your sleep before you fly, even by one or two days, is the single step that shortens recovery the most.
Is it better to sleep on the plane or stay awake?
Sleep when it is night for your body clock, which is often not night where the plane is. This plan marks the stretch of the flight that falls in your body-clock night as the best time to sleep. A sleep debt from one night of travel is largely made up the next night; the misaligned body clock is what makes jet lag last for days.
