Jet lag results from a mismatch between a person’s circadian (24-hour) rhythms and the time of day in the new time zone. It can affect your mood, your ability to concentrate, and your physical and mental performance. 

If you are expected to begin work immediately after arrival, jet lag can have potentially negative consequences. Fortunately, you can take steps to minimize the effects of jet lag. 

What to know 

Be aware that adjusting to a new time zone may take several days. If you are going to be away for just a few days, it may be better to stick to your original sleep and wake times as much as possible, rather than adjusting your biological clock too many times in rapid succession. 

Eastward travel generally causes more severe jet lag than westward travel because traveling east requires you to shorten the day, and your biological clock is better able to adjust to a longer day than a shorter day. 

Fortunately for globetrotters, a few preventive measures and adjustments seem to help some people relieve jet lag, particularly when they are going to spend more than a few days at their destination: 

Before travel 

During the 2–3 days before a long trip, get adequate sleep. You can make minor changes to your sleep schedule. For example, if you are traveling west, delay your bedtime and wake time progressively by 20- to 30-minute intervals. If you are traveling east, advance your wake time by 10 to 15 minutes a day for a few days and try to advance your bedtime. 

Decreasing light exposure at bedtime and increasing light exposure at wake time can help you make these adjustments. When you arrive at your destination, spend a lot of time outdoors so your body gets the light cues it needs to adjust to the new time zone. Take a couple of short 10–15 minute catnaps if you feel tired, but do not take long naps during the day.  

During travel 

Although it may be tempting to drink alcohol to relieve the stress of travel and make it easier to fall asleep, you’re more likely to sleep lighter and wake up in the middle of the night when the effects of the alcohol wear off. Alcohol actually disrupts sleep and can provoke obstructive sleep apnea. 

Caffeine can help keep you awake longer, but caffeine also can make it harder for you to fall asleep if its effects haven’t worn off by the time you are ready to go to bed. Therefore, it’s best to use caffeine only during the morning and not during the afternoon.  

Try to sleep on the plane, where appropriate. Taking sleep medications during a flight should be considered with caution because your lack of movement during the flight could increase the chance of getting deep vein thrombosis (blood clot). 

After you arrive 

If you can, schedule meetings or activities for a time of day you know you will be more alert. Eat meals at the appropriate local time can also help you adjust. 

Try to spend time outdoors and have access to natural daylight, which helps adjust your body to the new time zone. Additionally, drink plenty of water. Avoid alcohol or caffeine until you are acclimated to the new time zone. 

If you are sleepy during the day, take short (20–30 minutes) naps may help you to feel better during the day and still sleep through the night. 

What about melatonin? 

Your body produces this hormone that may cause some drowsiness and cues the brain and body that it is time to fall asleep. Melatonin builds up in your body during the early evening and into the first 2 hours of your sleep period, and then its release stops in the middle of the night. 

Melatonin is available as an over-the-counter supplement. Because melatonin is considered safe when used over a period of days or weeks and seems to help people feel sleepy, it has been suggested as a treatment for jet lag. 

But just how effective melatonin can be for treating jet lag is controversial, and its safety, when used over a prolonged period, is unclear. Some studies find that taking melatonin supplements before bedtime for several days after arrival in a new time zone can make it easier to fall asleep at the proper time. Other studies find that melatonin does not help relieve jet lag. 

Sources: National Heart, Lung, and Blood Institute, Centers for Disease Control and Prevention