Jet lag from westward to eastward travel typically lasts about one day for every time zone you cross. Fly from New York to London (five time zones east), and you’re looking at roughly five days before your body fully adjusts. That’s noticeably slower than the return trip westward, where most people recover about 50% faster.
Why Eastward Travel Hits Harder
Your body’s internal clock doesn’t run on exactly 24 hours. It naturally drifts slightly longer, closer to 24 hours and 10 to 20 minutes. This means your body finds it easier to stretch the day a little longer (what happens when you fly west) than to shorten it (what eastward travel demands).
When you fly east, your body has to “advance” its clock, falling asleep earlier and waking up earlier than it’s used to. That works against the natural drift. The CDC estimates an average adjustment rate of about 1 hour per day for eastward travel, compared to 1.5 hours per day for westward travel. So a six-time-zone eastward trip could take a full six days to recover from, while the same trip westward might take only four.
What the First Few Days Feel Like
Symptoms typically show up within the first one to two days after landing. The most common complaints are difficulty falling asleep at night, heavy daytime fatigue, trouble concentrating, and digestive issues like nausea or irregular bowel habits. For eastward trips, the sleep disruption tends to be the defining feature: you’ll find yourself wide awake at 2 or 3 a.m. local time while feeling desperate for a nap by early afternoon.
The worst of it usually hits on days two and three, when the gap between your internal clock and local time is still wide but the initial adrenaline of travel has worn off. From there, symptoms gradually ease as your clock shifts forward roughly an hour each day. By the midpoint of your recovery window, sleep timing is often close to normal, though low-grade fatigue and minor digestive symptoms can linger a day or two beyond that.
Recovery Timelines by Trip Length
- 3 time zones east (e.g., Los Angeles to New York): about 3 days
- 5 time zones east (e.g., New York to London): about 5 days
- 6 time zones east (e.g., Chicago to Paris): about 6 days
- 8–9 time zones east (e.g., New York to Dubai or beyond): 8 to 10 days, sometimes longer
These are averages. Individual variation is real, and some people consistently adjust faster or slower than the one-day-per-zone rule suggests.
Age Makes Sleep Disruption Last Longer
Research on older adults adjusting to a six-hour eastward shift found something interesting. The circadian rhythm itself (the timing of core body temperature cycles) adjusted at roughly the same speed in older and younger people. But the sleep disruption and daytime sleepiness lasted significantly longer in older adults, showing little of the gradual improvement that younger subjects experienced over the same period. In other words, your internal clock may reset on schedule as you age, but the quality of your sleep takes longer to catch up.
How to Speed Up Adjustment
The most powerful tool for resetting your clock is light exposure, timed correctly. The key concept is simple: after eastward travel, you need morning light and should avoid light in the late night and early morning hours before sunrise. Specifically, getting bright light in the first three to four hours after waking helps push your clock earlier, which is exactly what eastward adjustment requires. Going outdoors without sunglasses is the easiest way to do this.
Equally important is avoiding light at the wrong time. In the first couple of days after arrival, light exposure very early in the morning (before your body thinks it’s dawn) can actually push your clock in the wrong direction, making jet lag worse. If you wake up hours before local sunrise, keep lights dim and consider wearing blue-light-blocking glasses until the sun is up.
Before your trip, you can get a head start by shifting your sleep schedule earlier by about one hour per day for a few days. Pair this with bright light exposure in the first three to four hours after waking each morning. Even two or three days of pre-trip adjustment can meaningfully reduce the severity of jet lag on arrival.
Practical Tips for the First Week
Get onto local meal times immediately. Your digestive system has its own clock, and eating at local breakfast, lunch, and dinner times sends a strong signal to your body about the new schedule. Avoid heavy meals in the middle of the night, even if you’re awake.
Caffeine can help with daytime alertness but cut it off by early afternoon local time. If you use it too late, you’ll undermine the very sleep you’re trying to normalize. Short naps of 20 to 30 minutes are fine if you’re struggling through the afternoon, but longer naps will delay your adjustment.
Exercise during the day, particularly outdoors in natural light, supports faster adaptation. Even a 30-minute walk in the morning combines two of the most effective reset signals: physical activity and bright light. Avoid intense exercise close to bedtime, as it can make the already difficult task of falling asleep earlier even harder.
For trips crossing only two or three time zones, most people barely notice jet lag or recover within a couple of days without any special effort. The strategies above become more important as the number of time zones increases, particularly for trips crossing five or more zones eastward, where the recovery window stretches to nearly a week.