Jet lag

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Jet lag

Jet lag — Learn how to put it to rest.

Cherry trees are blooming in the Bois de Boulogne, the museums are mercifully free of tourists, and in the pale sunshine, couples browse the bookstores on the Left Bank. It's April in Paris, and you should be strolling the boulevards or sitting in Les Deux Magots. Instead, you're stretched out on the high-thread-count duvet in your hotel room, too jet-lagged to open the blinds or see anything more French than the Perrier on your nightstand.

It doesn't matter that you're young and fit or that you've made the New York to Paris run before. Jet lag, also called time zone change syndrome, is no respecter of persons — anyone can get it, even children though people over 50 are more susceptible. And it doesn't matter how many frequent flier miles you've logged. Although jet lag isn't inevitable, you're likely to experience some degree of jet lag whenever you cross three or more time zones.  The intensity and duration of your symptoms usually increase with the number of time zones you pass through, and you may find it harder to fly east, when you "lose" time, than to fly west, when you gain it back.

Jet lag isn't life-threatening, but it's a sleep disorder that affects millions of people every year. It steals precious vacation time — you need about a day to recover for each time zone crossed — interferes with global business and hijacks international diplomacy; more than one diplomat has confessed to sleepwalking through negotiations after a long flight. Jet lag is considered such a pervasive problem for frequent fliers — including flight attendants and pilots — that at least one airline has hired a sleep specialist to help them cope.

If it's Tuesday, it must be Wednesday

Jet lag occurs because crossing multiple time zones puts your internal clock, which regulates your sleep-wake cycle, out of synch with the time in your new locale. For instance, you lose six hours on a typical New York to Paris flight. That means that if you leave New York at 4:00 p.m. on Tuesday, you arrive in Paris at 7:00 a.m. Wednesday. According to your internal clock, it's 1:00 in the morning, and you're ready for bed, just as the City of Light is waking up. And because it takes a few days for your body to adjust, your sleep-wake cycle, along with most other body functions, such as meal times and bowel habits, remains out of step with the rest of Paris.

No wonder, then, that jet lag can keep you holed up in your hotel, with symptoms that may include:

  • Disturbed sleep — such as insomnia, early waking or excessive sleepiness
  • Irritability
  • Difficulty concentrating or functioning at your usual level
  • Headaches
  • Muscle soreness
  • Stomach problems, constipation or diarrhea

Not everyone experiences jet lag, and symptoms can vary widely. Most people feel the effects after crossing at least three time zones, but some may be uncomfortable after shorter flights, and others go through something akin to jet lag when the time changes in the spring and fall. Animals, too, seem sensitive to disruptions of their circadian rhythms — the innate daily round of sleep and waking that corresponds to the 24-hour cycle of day and night.

Can this vacation be saved?

Like cures for the common cold, jet lag remedies abound. How effective they are is a matter of some debate, but most experts agree on a few basic rules:

  • If you have an important meeting or conference — anything that requires you to be in top form — try to arrive a few days early to give your body a chance to adjust.
  • Get plenty of rest before your trip. Starting out sleep-deprived makes jet lag worse.
  • If you're traveling east, try going to bed one hour earlier each night for a few days before your departure. Go to bed one hour later for several nights if you're flying west. If possible, eat meals closer to the time you'll be eating them at your destination.
  • Drink plenty of water before, during and after your flight to counteract the dehydrating effects of bone-dry cabin air. It's not clear whether dehydration actually causes jet lag, as some experts maintain, but there's no doubt it makes symptoms worse. For the same reason, avoid alcohol and caffeine, both of which dehydrate you further.
  • Try to sleep on the plane if it's nighttime at your destination. Earplugs, headphones and eye masks can help block out noise and light. If it's day where you're going, resist the urge to sleep.
  • Set your watch to the new time before you leave. Once you reach your destination, try not to sleep until nighttime, no matter how tired you are.

    Use light to reset your internal clock; it's the most powerful natural tool for regulating the sleep-wake cycle. That's because the pineal gland, a part of the brain that influences circadian rhythms, responds to darkness and light transmitted by the optic nerve. At night, the pineal gland releases the sleep-promoting hormone melatonin; during the day, melatonin production stops.

    Plan ahead to determine the best times for light exposure based on your origination and destination points and overall sleep habits. An online jet lag calculator may make this task easier.

    For example, a poor sleeper traveling from New York to Paris is advised to seek light between 11:30 a.m. and 2:00 p.m. on the first day in France and between 8:30 a.m. and 11:00 a.m. on the second day. By the third or fourth day, the traveler's internal clock should mesh with the local time. The results are even better if light exposure is combined with exercise such as walking or jogging.

    Avoiding light at certain times is every bit as important as taking it in at others. The hypothetical New York to Paris traveler should avoid light from 9:00 a.m. to 11:30 a.m. on day one and from 6:00 a.m. to 8:30 a.m. on day two for best results. In the real world, that can be a challenge. At night, draw the blinds or drapes in your hotel room or use a sleep mask. During the day, dark glasses can help block out light.

  • Consider melatonin supplements. Melatonin's reputation as a jet lag remedy and sleep aid has had its ups and downs. Some studies indicate that it's effective; other studies have found the opposite. The latest research seems to show that melatonin does indeed aid sleep during times when you wouldn't normally be resting, making it of particular benefit for people with jet lag. Small doses — as little as 1/3 milligram — seem just as effective as doses of 5 milligrams or higher. Some scientists think that higher doses actually overload the body, causing the melatonin to become ineffective. If you do use melatonin, take it 30 minutes before you plan to sleep or ask your doctor about the proper timing.
  • Investigate other remedies. Most red-eye regulars have a favorite jet lag cure, from aromatherapy or homeopathy to special diets. Many of these diets alternate days of feasting and fasting and high-protein and low-protein meals. Though no anti-jet-lag diet has definitively been shown to work, some people swear by them. If the diets themselves seem too complicated, you can approximate their effects by simply eating high-protein foods to stay alert and carbohydrates when you want to sleep. Most alternative jet lag therapies aren't harmful and may be worth a try if nothing else helps.
  • Take a slow boat. Jet lag got its name for a reason. Crossing time zones slowly allows your body more time to adjust and usually eliminates the worst jet lag symptoms.

Last Updated: 07/11/2006
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