Roxanne Nelson
CONSUMER HEALTH INTERACTIVE

Note: This article has been localised for an Irish audience.

Jet lag is an unfortunate by-product of the era of rapid air travel. Your body has a 24-hour biological clock that controls your daily cycles of sleeping, eating, and many other functions, which are known as circadian rhythms. When you travel across several time zones, your day becomes longer or shorter than 24 hours, disrupting your normal body rhythms. If you've just flown from Dublin to Bangkok, for example, you may be wide-awake and ravenous at 2 a.m. That's because your body is still on Dublin time and hasn't had a chance to acclimatise.

Fatigue, insomnia, headaches, light-headedness, and gastrointestinal upsets such as diarrhoea and constipation are the most common ones. You may also feel disoriented and have trouble with decision-making and short-term memory. For example, you may end up returning to your hotel room three times because you can't remember locking the door. It is estimated that for each time zone you cross, you need about a day to fully adjust.

The more time zones you cross, the greater your chances of becoming jet-lagged. Also, travelling east is generally tougher, because the regular 24-hour day is shortened and bedtime arrives earlier. Trying to sleep before your internal clock says you are ready can be frustrating, and getting up for breakfast in the morning is even harder. Travelling west, you get a longer day, and you have to stay up later and sleep later, which is generally easier to do.

If you travel across several time zones frequently, you'll probably suffer some degree of jet lag, and you won't be alone. Jet lag has caused many a diplomatic blunder, ruined countless athletic performances, and made for lots of poor business decisions.

Unfortunately, there's no foolproof means of staving off jet lag, but here are some tips on how to minimise its effects:

•Before departure, gradually shift your sleep-wake cycle -- at the rate of one hour per day -- to match that of your destination. Once you're in the air, reset your watch right away. If it's night at your destination, try to sleep on the plane. Wearing an eye mask and earplugs or headphones can diminish light and noise. To avoid getting jostled by other passengers, ask for a window seat. If it's daytime where you're headed, stay awake. Keep your light on. Read a thriller. Get up frequently and walk the aisles.

•During your flight, drink plenty of water or juice to offset dehydration from the dry cabin air, which can exacerbate the effects of jet lag. Don't choose alcoholic or caffeinated drinks, which will make you even more dehydrated.

•If you arrive in the daytime, resist the urge to nap. Try to stay up until local bedtime. Spend as much time as possible outdoors in natural light, which helps reset your biological clock.

•You may also want to consider taking a short-acting sleeping pill while on the plane and for the first few nights after arrival, if you're having trouble adjusting to local time and are unable to sleep. However, all sleeping pills, both over-the-counter and prescription types, can have a hangover effect. Instead of feeling alert and well-rested, you may wake up feeling groggy.

Also, accumulating evidence suggests that sleeping in the cramped seats of an aircraft may increase your risk of developing deep vein thrombosis. It is advisable to get up and walk around the plane at regular intervals.

A researcher at the Argonne National Laboratory in France came up with an anti-jet lag diet a while back -- a complex protocol of fasting, precisely scheduling meals, and alternating foods high in protein and carbohydrates. In two controlled studies most people found the diet to be slightly helpful, but a few reported that it actually worsened their jet lag. What's more, you have to begin the regimen several days before departure, which isn't practical for many people. Researchers are investigating a simpler method of using diet to prevent jet lag based on the idea that foods high in carbohydrates, such as pasta, may promote sleep, while foods high in protein can help you stay awake. So, if you arrive at 8 a.m. and your eyelids are drooping, forgo the crumpets and order an omelette instead.

This article has been revised by Vhihealthe for its audience and may contain, among other things, information or medical practices that are unique to Ireland. Neither Consumer Health Interactive nor the original author make any warranty as to the accuracy of the article as revised, and assume no responsibility for modified content.

First published May 31, 2001
Copyright © 1999 Consumer Health Interactive

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