How Long Does Jet Lag Last? Days to Recover for Popular Routes
Jet lag usually lasts about 1 day for every time zone you cross flying east, and a little less flying west. According to the CDC, the body clock adjusts by roughly 1 hour a day after eastward travel and 1.5 hours a day after westward travel. So a flight from New York to London (5 hours ahead) can take about 5 days to fully adjust to, while the return trip takes about 3 to 4.
Key facts
- The body clock shifts about 1 hour a day after flying east and about 1.5 hours a day after flying west.
- Flying east is usually harder, because you have to fall asleep earlier than your body wants.
- Shifting your sleep by 1 hour a day for 2 to 3 days before you fly gives you a head start.
- Light at the right time of day is the most powerful way to reset your body clock.
Why jet lag happens
Your body clock runs on a roughly 24-hour cycle and is reset each day mainly by light. When you fly across time zones, local time changes instantly but your body clock doesn’t. Until it catches up, you feel sleepy, hungry or alert at the wrong times, and you may sleep badly, feel foggy or have stomach trouble.
Estimated recovery times
| Route | Time difference | Direction | Days to adjust (approx.) |
|---|---|---|---|
| New York → London | 5 hours ahead | East | 5 |
| London → New York | 5 hours behind | West | 3–4 |
| Vancouver → London | 7 hours ahead (winter 2026–27) | East | 7 |
| Los Angeles → Tokyo | 17 hours ahead, treated as 7 hours behind | West | 5 |
| Toronto → Paris | 6 hours ahead | East | 6 |
| Sydney → London | 11 hours behind (in January) | West | 7–8 |
| New York → Los Angeles | 3 hours behind | West | 2 |
Estimates use the CDC’s adjustment rates. Time differences change during the year when one place changes its clocks and the other doesn’t. Check the exact difference for your dates on ClockNow’s time zone converter.
Note that BC no longer changes its clocks, so from November 2026 Vancouver is 7 hours behind London in winter instead of 8.
Why flying east is harder
Most people’s body clocks naturally run slightly longer than 24 hours, so it’s easier to stay up later (as after flying west) than to fall asleep earlier (as after flying east). After a long flight east, you may lie awake at bedtime and struggle to wake up in the morning.
How to reduce jet lag
Before you fly
- For 2 to 3 days before an eastward flight, go to bed and get up 1 hour earlier each day. Before a westward flight, go 1 hour later.
- Arrive well rested. Starting a trip with sleep debt makes jet lag worse.
On the plane
- Set your watch to destination time.
- Sleep if it’s night at your destination; try to stay awake if it’s daytime there.
- Drink water and go easy on alcohol and caffeine.
After you land
- Flying east: get bright light in the morning and avoid bright light in the evening for the first few days.
- Flying west: get light in the late afternoon and evening, and avoid bright light early in the morning.
- Eat meals and go to bed on local time from day one.
- Keep naps short, 20 minutes or less, so you can still sleep at night.
- For trips of 2 days or less, it may be easier to stay on home time.
Our jet lag planner builds a day-by-day plan for your own route and usual sleep times.
What about melatonin?
The CDC says melatonin may help some travellers and that 0.5 to 1 mg is often enough; doses above 5 mg aren’t recommended. Talk to a doctor or pharmacist first. Read more in does melatonin work?
Sources
- CDC Yellow Book: Jet lag disorder
- National Institute of Neurological Disorders and Stroke: Brain basics: understanding sleep
Frequently asked questions
How long does jet lag last after flying 8 hours east?
About a week, at roughly 1 hour of adjustment a day.
Is it better to sleep or stay awake when you arrive?
If you land in the morning, stay awake until a normal local bedtime, with at most a short nap.
Does jet lag get worse with age?
Many older travellers report finding it harder, and their sleep is often lighter, so they may need extra time to adjust.
