MINIMIZING, PREVENTING THE EFFECTS OF JET LAG

10-17-2000

A recognized medical malaise that affects an estimated 96 percent of travelers, jet lag is caused by disruptions in the circadian rhythms, what sleep researchers call "external and internal desynchronization." 

According to the generally accepted theory, long-distance flights force the body to cope with sudden shifts from day to night, cramped in desert-dry planes, coaxed to sleep at odd times.  The length of the flight is less afactor than the number of time zones the trip crosses. A 10-hour north-south flight that stays in one or two times zones is generally much less disruptive than a seven-hour, east-west journey.

Travelers who smoke, have rigid eating or living habits, pack at the last minute, rush to catch planes and fly from west to east are likely to suffer the most severe and longest- lasting symptoms, while those with more flexible routines or the ability to sleep easily fare better. 

Modern jet-lag cures rely on medications such as melatonin or ambien, but most travelers follow a simpler strategy.  When flying west to east, they avoid heavy food and drink that will make it harder for them to sleep on arrival. When they fly the other way, they stretch their day with a few cups of caffeinated coffee or tea. 

On long flights, they make a point to get up and stretch their legs every few hours.  To combat the dehydration that can result from spending hours on end in the arid atmosphere of an airplane cabin, they drink lots of water and go easy on the alcohol, which can be two or three times more potent than when consumed on the ground. Even too much fruit juice can have a negative effect. 

One good preventative is bringing your own bottle of water to sip on during the flight. In addition to keeping yourself hydrated, this will contribute to your exercise quotient by forcing you to periodically get up and move about the cabin to the restrooms. 

Since getting some shuteye en route also helps, do whatever you can to catch a few winks. Blindfolds, ear plugs, neck rests and inflatable pillows are all useful props. Removing your shoes to reduce pressure on your feet will also help. 

Flying first class or business class is also preferable, since there will be more room to stretch out and fewer disturbances, and the air tends to be fresher in the front of the plane. 

Some travelers rely on sleeping pills on the plane, but many chemi cal combinations contain antihistamines that can make dehydration worse and leave you feeling groggy the next day. Sleeping pills can also be dangerous, as the comatose state they induce can contribute to the formation of blood clots in space-cramped legs. 

There are chemical cures in addition to sleeping pills. For several years, melatonin, a substance which occurs naturally in the body, has been trumpeted as a wonder cure for jet lag, but the evidence has largely been based on experimental data with animals.

Several recent studies, however, have cast doubt on the assumptions. For example, a study of the personal experience of 257 Norwegian doctors published this year in the Journal of American Psychiatry found that melatonin tablets were no more effective than a placebo at preventing the symptoms of jet lag.  For a more holistic approach, the government's Argonne National Laboratories developed a diet designed to help travelers gradually reset their biological clocks. 

The basic idea is to alternate feast days and fast days. One day eat low-calorie, low-carbohydrate foods, with lots of salads and fresh fruit. The next day, feast on foods rich in protein and carbohydrates, such as pasta and meat. 

Ideally, you need a day in advance of leaving for each time zone you'll be crossing. For example, a trip from the East Coast to Europe takes five days of the regimen. Time your diet so you fast on the day of travel and feast on the day you arrive. Clearly, this program works best for people who have lots of time to prepare for their trips. 

Since light and dark is another way the brain sets its internal clock each day, another approach uses strong, timed doses of light to advance that clock appropriately. 

Although there is a complicated formula to determine the particulars, the light cure's first step is to determine whether you are a "morning lark," someone who does well in the a.m. hours, or a "night owl," whose energy naturally peaks later in the day. Then counter the effects of jet lag with massive doses of bright light at the proper time. 

Calculating when and how much light you should get depends on the direction you're flying, how many time zones you'll be crossing and how much sleep you'll lose. Light received before 5 a.m. home time shifts the traveler's time clock westbound. Later light shifts the internal clock eastbound. 

Travelers can take the necessary dose of light in artificial settings with a $300 "light visor." A cheaper alternative is simply to take a walk outside in the daylight, once you land, of course.  None of these cures claims to completely prevent jet lag, only to make long-distance transitions easier. 

Your choice of flight times also can be important. Some departure times are better for different types of travelers. 

Morning folks who adjust rapidly to new time zones can take advantage of daytime flights from the United States to Europe.  Night owls may find the last flight at night lets them sleep on the plane. In most cases, experts advise travelers to try and adjust their sleep schedule as quickly as possible to the local routine. 

The primary exception are travelers on very short trips of a day or two to Asia or Europe. They may do better not trying to adjust their internal clocks at all, and instead stay on their home time.

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