Jet lag is caused by flying in an airplane and crossing one or more time zones, which can disrupt the body's sleep and wake cycle (circadian rhythms). Jet travel across time zones may make it difficult for you to fall asleep, stay asleep, or stay awake during the day.

The effects of jet lag usually are greater if you are going from west to east than from east to west.

The symptoms of jet lag may take one to several days to go away:¹

• When you fly east, the number of days it takes to recover from jet lag will be about two-thirds the number of time zones you cross. For example, if you cross six time zones, it will take you about 4 days to get back to normal.
• When you fly west, the number of days to recover equals about half the number of time zones. So if you cross six time zones, it will take you 3 days to recover.

Melatonin is a hormone the body makes that regulates the cycle of sleeping and waking. Taking melatonin may help "reset" your sleep and wake cycle. Some studies show that using it reduces how much jet lag people report on both eastward and westward flights², but other studies have not shown a benefit.³

You can try taking melatonin to reduce the symptoms of jet lag. Suggestions about times and dosages vary among researchers who have studied melatonin. Recommendations include:

• Taking melatonin after dark the day you travel and after dark for a few days after arriving at your destination.⁴
• Taking melatonin in the evening a few days before you fly if flying eastward.¹

The long-term side effects of melatonin have not been well studied. If you have epilepsy or are taking blood thinners such as coumadin (Warfarin), talk to your doctor before using melatonin.

There are other things you can do to decrease the effects of jet lag. Be rested before your flight, and try to walk around during the flight so that you are not confined to cramped spaces for long periods of time. Drink lots of water, because the air in jets tends to be dry. Vitamins and herbal remedies that can be bought without a prescription can also be tried to help reduce jet lag.