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 treatments seem to help some people relieve jet lag:

• Adjust your biological clock. Several days before traveling to a new time zone, gradually shift your sleeping and eating times to coincide with those at your destination. You can also adjust your clock by using light therapy. This involves being exposed to special lights, many times brighter than ordinary household light, for several hours near the time you want to wake up. Alternatively, after arrival, spend a lot of time outdoors to make sure your body gets the light cues it needs to adjust to the new time zone.
• Avoid alcohol and caffeine. 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. Caffeine can help keep you awake longer, but caffeine can also 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.
• What about melatonin? Your body produces this hormone that makes you drowsy. Melatonin builds up in your body as the night progresses and decreases when daylight arrives. 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 contribute to feeling sleepy, it has been suggested as a treatment for jet lag. But melatonin’s effectiveness 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 to relieve jet lag.

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.