You know the symptoms - insomnia, fatigue, irritability, stomach upset, headache, disorientation, and lack of concentration. While you were winging your way across the globe, your body clock was lagging behind. You may have been traveling by jet, but your body clock was coming by slow boat or train. Eventually, your body clock will catch up, but it may take a full day or more for each time zone you've crossed.
If you were to fly from San Francisco to Rome, for example, you might be crossing nine time zones. That means that nine days after you arrived, your biological rhythms would be fully adapted to local time. But by then, it would likely be time to turn around and go back home. When your plane touched down in San Francisco, you would be confronted with jet lag all over again, because now your inner clock would be stuck behind in Rome.
As a rule, it's easier to adapt when you fly west. As I mentioned earlier, your body clock actually operates on about a twenty-five-hour schedule. Flying west demands that you stretch out your day, going to bed later than you did in your hometown. Your native twenty-five-hour cycle helps you stay up later than normal. Flying east, however, demands that you compress your daily schedule, taking away this built-in advantage.
Many travelers rely on sleeping pills to cope with jet lag. But sleeping pills have limited usefulness. Although they help you sleep, they do not adjust your body clock. What they do is send a powerful sleep signal to your brain that simply overwhelms the subtler messages coming from your body clock, allowing you to sleep even though your body clock says that it's the middle of the day. Thus, although the pills alleviate one of the primary symptoms ofjet lag - fatigue - they do not address the underlying problem.
In a search for a more natural solution, a number of enterprising people have devised "jet lag diets," complicated dietary regimes that involve eating carbohydrates or proteins at specific times of the day and timing your consumption of caffeine. These diets rely on the fact that eating high-protein foods tends to energize you and eating high-carbohydrate food can make you drowsy. Thus manipulating your diet may make it easier for you to fall asleep or stay awake as your new schedule demands. But jet lag diets do not reset your body clock. Like sleeping pills, they treat only the symptoms.
Light therapy is more effective than dietary interventions because light has a direct effect on your body clock. By exposing yourself to bright light at certain times of the day and avoiding light at others, you hasten your body clock's transition to local time. The most effective schedule of light therapy has been worked out by doctors Alfred Lewy and Surge Daan and popularized in a number of jet lag handbooks. These handbooks take into account the number of time zones you've crossed and the direction you traveled. But drawbacks to this technique include having to arrange your activities around your need for light and darkness. You may also have to pack along a bulky and fragile light box or other lighting device.
Given the drawbacks to these jet lag remedies, it's no wonder that a growing number of frequent flyers are tucking a bottle of melatonin into their carry-on luggage. The person who has been most instrumental in developing a melatonin therapy for jet lag is my longtime colleague Josephine Arendt. Ph.D., professor in the department of biochemistry at the University of Surrey, Guildford, England. The therapy is simple yet effective. The day you arrive at your new destination, you take 5 milligrams of melatonin an hour before bedtime, local time. Melatonin performs tow jobs simultaneously - it helps you sleep better, and it speeds up the adjustment of your body clock. Furthermore, it accomplishes both of these ends without inconveniencing you or causing negative side effects. Relieving jet lag is one of melatonin's most straightforward and effective uses. Several years ago, the recommended strategy was to take melatonin before leaving home. The melatonin adjusted the body clock before and during the flight, allowing people to arrive at their destinations symptom free. This protocol was followed by ten sports physicians and coaches from Italy who were attending the 1990 world karate championships in Mexico. They stayed in Mexico long enough to become adapted to local time. Before returning home, four of them took melatonin at four o'clock in the afternoon, which corresponded to bedtime in Italy. The remaining six served as controls. When the group arrived in Italy, "the four melatonin volunteers were found to be in perfect mental and physical condition...whereas the six controls showed the classic symptoms of jet lag for 2 to 3 days." (The reason that the current recommendation is to begin treatment upon arrival is that this protocol does not require any elaborate calculations about when to take melatonin.)
Another and larger study produced equally good results. French researchers conducted a jet lag study involving thirty volunteers who were scheduled to fly from the United States to France. One of the criteria for being included in the study was having had difficulty with jet lag in the past. On the day of the flight and for three days thereafter, the volunteers took either a placebo or a tablet that contained 8 milligrams of melatonin. The pills were taken between ten and eleven p.m., French time. The volunteers who took melatonin fared better in every measure tested, including quality of sleep, mood, and work efficiency.