Flying Europe to the United States is the easier direction: you are delaying your body clock, which is closer to what it does naturally. The difficulty is different rather than absent — a very long first day, and a strong pull to wake at 3am for the first few nights.
Paris or Berlin to New York is a six-hour westward shift, usually flown during the day and landing in the afternoon.
6h westward shift. ~4 days to full adaptation.
| Factor | This route |
|---|---|
| Direction | westward — 6 hours |
| Severity | moderate |
| Days to adapt | about 4 |
| Harder or easier direction | Easier. Delaying the body clock comes more naturally than advancing it. |
Westward asks the body clock to delay, which suits its natural drift, so this leg generally settles faster than the outbound one. The trap is the first day: you leave in the morning, fly for eight hours, and land in the early afternoon with an entire American evening still ahead of you. It is a very long day.
The second trap is the 3am wake. It is not insomnia — 3am in New York is 9am in Paris, so your body is simply waking at its usual hour in the wrong place.
The first full day at the destination. Note how much later the light window sits than it does on the eastward leg.
All times are destination local time, for a traveller who normally sleeps 11:00 PM to 7:00 AM. Enter your own hours in the jet lag tool for a schedule built around your sleep rather than this example.
| What to do | When |
|---|---|
| Bright light before bed (30+ min) | 3:30 PM - 6:30 PM |
| Avoid light on waking | 12:30 AM - 3:30 AM |
| Target sleep window | 6:30 PM - 2:30 AM |
| Melatonin (0.5 mg) | 5:30 PM - 6:30 PM |
Staying up to a local bedtime is the goal, but forcing it well past the point of usefulness makes the following day worse rather than better. Aim for a plausible local bedtime, not a heroic one — and get outside during the afternoon, which is doing more work than the willpower is.
Generally yes. Delaying the body clock suits its natural drift, so westward adaptation tends to come faster than the same shift eastward.
Because your body still thinks it is morning. A 3am wake in New York is 9am in Paris, which is simply your usual wake time arriving at the wrong moment.
Within reason. Staying up to a local bedtime helps, but forcing it far past the point of usefulness makes the next day worse. The plan works with the pull rather than against it.
Stay in dim light and rest rather than getting up into bright light, which would reinforce the early schedule you are trying to move.
For a six-hour shift, roughly four days with a plan, and often it feels manageable sooner than the eastward equivalent even though the calendar figure is similar.