Jet Lag From New York to London, Paris and Amsterdam: Small Shift, Big Misery

Why this route is hard

Every number on this page is small. London sits 5 hours ahead of New York for most of the year, and Paris, Amsterdam and Frankfurt sit 6. The Jet Lag Calculator rates it at about 5 days of recovery for London and 6 for the continent, using the research rule of roughly one day per zone flying east. By the standards of a Los Angeles to India trip, that is mild.

What makes it feel worse than the numbers is the flight itself. Almost every transatlantic flight from the East Coast leaves between 6 PM and 10 PM and lands between 6 AM and 10 AM local. The flight is 6 to 7 hours long, meal service takes the first hour and a half, and the cabin lights come back on 90 minutes before landing. Most people get 2 to 4 hours of fragmented sleep. You then step off the plane at 8 AM London time, which is 3 AM in New York, deep in the coldest part of your biological night, and walk into a full day.

So the jet lag on this route is really two problems stacked: a modest 5 hour advance of the body clock, and one nearly sleepless night on top of it. The body clock takes days to move. The lost sleep can be managed on day one, which is why the plan below treats the first day differently from the rest.

The direction matters too. Flying east means your body clock has to move earlier, a phase advance. The human circadian clock runs slightly longer than 24 hours, so it drifts later on its own and advances only reluctantly. That is why the same 5 hours flown westward, coming home, recovers about a day faster.

Flying out

Enter your route in the calculator and it produces a plan in three parts: prep nights before you fly, the flight, and arrival days. Here is what it does for a New York to London trip with two prep days and a usual bedtime of 10:30 PM.

Prep nights. Each prep night moves bedtime an hour earlier: 9:30 PM two nights before, 8:30 PM the night before. Wake time moves with it. An hour a night is about the most a body clock will accept without help, and two prep nights take two hours off the five you need to shift, which removes a full day from the arrival plan. Bright light after waking on those mornings and dim light in the last two hours before bed push the clock in the same direction.

The flight. No scheduled sleep window, because the flight is too short for one. Sleep as early in the flight as you can, and keep alcohol and long naps off the list. The alcohol trade-off is covered in the alcohol and sleep calculator.

First night in London. The plan's first sleep window runs midnight to 8 AM local time. That looks late for a work trip, but midnight in London is 7 PM in New York, which after two prep nights is about as early as your body can fall asleep. The two hours before it, from about 10 PM, are a dim-light window: low lamps, screens down, no bright bathroom light. Trying to force an 10 PM bedtime on night one usually means an hour of lying awake followed by a 3 AM wake, which sets you back.

Day one. Get outside in daylight in the morning, ideally for the hour after you wake. The plan marks 8 AM to 9:30 AM as the light window on the morning after the first night, and on the arrival morning itself, when you have not slept, the same rule applies: daylight, not the hotel room. Keep moving through the afternoon. If you nap, keep it under 30 minutes and finish before 3 PM.

Day two onward. Bedtime moves about 90 minutes earlier each night, so night two is around 10:30 PM local and night three is at your usual time. Morning light and a dim evening each day keep the shift moving. The plan reaches local time in 4 days for London and 5 for Paris, Amsterdam or Frankfurt, where the first-night window starts at 1 AM rather than midnight.

If you fly without prep nights, or you are reading this in a hotel room, switch the calculator to "I already landed". The plan then starts from tonight: a first sleep window of 2 AM to 10 AM London time, a light window from 10 AM, and the same 90 minute steps after that, reaching local time in 4 days.

Open the outbound plan for New York to London, or the New York to Paris, Amsterdam or Frankfurt version. Already there? Start from tonight.

Flying home

Europe to New York is the same 5 or 6 hours in the easy direction. Your body clock has to move later, a phase delay, which is the way it drifts on its own. The calculator estimates about 4 days of recovery from London and 5 from the continent, a day less than the outbound leg in each case.

The flight helps as well. Most westbound departures leave Europe between 9 AM and 2 PM and land in New York in the early to mid afternoon, so there is no overnight sleep to lose. You arrive tired from a long day, not from a sleepless night.

The plan for the return with two prep nights runs bedtime an hour later each night before you fly, 11:30 PM then 12:30 AM London time, with evening light and a dim first hour after waking to push the clock later. On the night you land, the sleep window is 9:15 PM to 5:15 AM New York time, which is the body's 2:15 AM London bedtime after the prep shift. Evening light from about 6 PM to 8:45 PM delays the clock; the first hour after waking is the light-avoidance window, so no bright kitchen light or a dawn run on day one.

The symptom to expect coming home is not trouble falling asleep but waking at 4 or 5 AM for two or three mornings. That is the delay still in progress. Staying in dim light until a normal wake time, and getting outdoor light in the late afternoon instead, closes the gap.

Open the return plan for London to New York, or the Paris, Amsterdam or Frankfurt to New York version.

Short trips

A two night trip to London is not worth adapting to. A 5 hour shift takes four or five days to complete, so by the time your clock has moved you are on the flight home, and then you pay the same price in reverse. For trips of three nights or fewer, the research advice is to stay as close to home time as the schedule allows: sleep late by local standards, hold meetings from late morning onward, and treat the evening as the productive part of the day, which it is on a New York clock.

Where that is not possible, use the "I already landed" plan for the nights you are there and accept that you will not finish it. Two nights of the plan still move you 3 hours closer to local time, which is the difference between a usable morning meeting and an unusable one.

From four nights upward, adapt. The prep nights and the light plan make the trip shorter in jet lag terms than in calendar terms, and a five night trip on the plan gives you three good days rather than one.

Light, melatonin and caffeine

For an eastward trip these are the three levers, in order of strength.

Light. Morning light advances the clock and evening light delays it, so the whole plan comes down to light in the hour or two after waking and dim light in the two hours before bed. Outdoor daylight is far stronger than any indoor lamp, even on an overcast London morning. The mistake most travellers make is the opposite pattern: a dark hotel room in the morning, then bright screens and restaurant lighting until midnight.

Melatonin. The Cochrane review by Herxheimer and Petrie found that in eastward-travel studies of five or more time zones, melatonin taken close to the target bedtime at the destination reduced jet lag symptoms. The doses studied were low, in the 0.5 to 5 mg range, with the lower end performing as well as the higher. That is what the research did; whether it suits you is a question for your doctor or pharmacist, particularly if you take other medication. The Melatonin Timing Calculator shows the timing the studies used for an advance.

Caffeine. Coffee is useful on the arrival morning and harmful in the evening, and on an advance the evening arrives early. With a midnight first-night bedtime, the Caffeine Cutoff Calculator puts the last coffee at about 3:30 PM local, and as bedtime moves earlier over the following nights the cutoff moves with it.

One more number worth knowing. A redeye that gives you three hours of sleep leaves a five hour debt before the time-zone shift even starts, and the Sleep Debt Calculator will show it does not clear in one night. An early bedtime on night two and three repays it faster than a long lie-in, which would only push your clock the wrong way.

Educational information, not medical advice. Consult a healthcare provider for sleep disorders or before taking any supplement.