This is general information, not medical advice. People differ in how they respond to travel and time changes. Talk with a doctor or other qualified professional before using sleep aids, melatonin or other supplements, or if you have a sleep disorder, a medical condition or a prolonged problem sleeping after travel.
What jet lag is
Jet lag is the mismatch between your body’s internal clock and the local time after you travel quickly across several time zones. Your body has a roughly 24-hour rhythm, often called the circadian rhythm, that influences when you feel sleepy or alert, when you feel hungry and even your body temperature. It is guided mainly by light, and it takes time to shift.
When you land in a place where midday is the middle of your body’s night, the result can include daytime sleepiness, trouble falling asleep at the new bedtime, waking too early, poor concentration, low energy, irritability and an unsettled stomach or appetite. These effects are usually temporary. The experience varies widely. Some people barely notice a few time zones, while others feel off for days.
Why direction and distance matter
Jet lag generally gets more noticeable as the number of time zones crossed increases. Travel north or south within the same time zone does not typically cause it, although long flights can still be tiring for other reasons.
Direction also matters for many people. Traveling east, where you need to fall asleep earlier than your body wants, is often described as harder than traveling west, where you stay up later. This is a general pattern, not a rule, and individuals differ.
Age, how rested you were before the trip, the length of your stay and your usual schedule can all play a role. For a very short trip of a day or two, some travelers choose to stay roughly on home time rather than adjusting, though that depends on the schedule of the trip.
Light is the main signal
Light exposure is generally considered the strongest cue for resetting the body clock. The timing of light matters, not only the amount. A general idea many sources describe is:
- After traveling east, morning light at the destination tends to help shift the clock earlier, while bright light late in the evening may make adjusting harder.
- After traveling west, late afternoon and evening light tends to help shift the clock later.
The details depend on how many time zones you crossed, and the advice for large shifts can be more complicated, because light at the wrong time can push your clock the wrong way. If you are not sure, a simple rule of thumb is to spend time outdoors during local daytime and keep your evenings dim and calm. Sunglasses or dim rooms can help when you want to avoid light.
Habits people commonly use
None of these is a guaranteed cure, and the research on many of them is mixed or limited. They are simple, low-risk steps that many travelers find helpful.
Adjust sleep gradually before you go. Some people shift bedtime and wake time by a short amount for a few days before a long trip, in the direction of the destination. This is optional and may not suit your schedule.
Move to local time early. On the plane, you might set your watch to the destination time and try to sleep or stay awake in line with it. Once you land, follow the local schedule for meals and bedtime as much as you reasonably can.
Keep naps short. If you need to nap, a short one earlier in the day is often suggested, since long or late naps can make it harder to sleep at night. Napping is a trade-off, and it helps to think about when it helps and when it hurts.
Be careful with caffeine. A cup of coffee or tea in the local morning can help with alertness. Caffeine later in the day can delay sleep, and its effect can last for hours.
Go easy on alcohol. Alcohol may make you drowsy, but it often disrupts sleep later in the night, and plane cabins are dry.
Drink water. Dehydration does not cause jet lag, but being dehydrated can add to tiredness and headaches. Sip fluids during the flight.
Eat with the local clock. Meal timing is another cue for the body. Eating at local mealtimes, and keeping meals light if your stomach feels unsettled, may help your body adapt.
Get gentle movement. A walk outside in daylight combines light exposure and activity, and is a reasonable first step after a long flight.
Making the room ready for sleep
On your first nights, treat sleep conditions seriously. Keep the room dark, cool and quiet, use an eye mask or earplugs if you like them, and put screens away well before bed because evening screens can make winding down harder. A consistent wind-down routine can be just as useful on the road as at home, and if you struggle at night, it helps to know what a sound sleep routine looks like.
If you wake up in the middle of the night, avoid checking the clock repeatedly. Some people find it helps to get up briefly, keep lights low and do something quiet before trying again. Try not to lie in bed anxious about the lost sleep, since worry can make sleep harder.
Melatonin and other aids
Melatonin is sometimes mentioned in connection with jet lag. It is a hormone the body makes, and it is sold as a supplement in some countries. We are not able to recommend doses, products or timing here. Whether it is appropriate depends on your health, other medications and local regulations, and supplements can interact with medications or have side effects. Ask a doctor or pharmacist before using it, and remember that food, light and routine come first. The same goes for prescription sleep medication, which should only be used under professional guidance.
When to get help
Jet lag normally eases within days as the body clock adjusts, although it can take longer after large shifts. See a healthcare professional if sleep problems continue well after you have settled in, if you feel persistently low or anxious, if you have unusual symptoms such as chest pain, swelling or pain in one leg, or shortness of breath after a long journey, or if you work irregular hours across time zones and feel unwell as a result. Some of these can be urgent. If symptoms feel serious, seek emergency care.
Keep expectations realistic
You may still feel off for a day or several, however carefully you plan. It can help to avoid scheduling important decisions, long drives or demanding activities right after landing when possible, and to give yourself a lighter first day. Results vary, and the habits above are best seen as ways to make the adjustment a little smoother rather than to remove it.