Can you avoid jet lag?

Most well-travelled people have opinions about minimising jet lag, but what strategies really do help?

Is it potty to travel halfway around the world for a weekend break, bearing in mind the effects it might have on your system? The answer to that partly depends upon how tiring and stressful an individual generally finds long-haul trips, but whatever your reaction, you can do a lot to minimise the effects.

Jet lag is the disruption of normal circadian rhythms caused by crossing several time zones. It is exacerbated by long-flight fatigue and disrupted sleep routines. People experience low energy, headache, irritability and reductions in both physical and mental performance capabilities. Travelling across meridians causes difficulties both in getting to sleep and in staying asleep. Many travellers also experience feelings of sudden tiredness and hunger at unusual times.

It is generally accepted that it takes about a day to adjust to each hour of time difference, so a seven-hour flight will have significant affects for a week, and the grouchiness persists for longer. Subtle physiological disruptions can be measured up to three weeks after a long-haul flight. Flying west is better tolerated than eastward journeys because the natural circadian rhythm is for a 25-hour day so the body can most easily "absorb" a longer day.

Timings of flights influence how awful you feel on arrival. A little light exercise before and after the flight is beneficial and it is best to avoid in-flight alcohol; sleeping tablets are best reserved for after (rather than during) the flight because of the increased risk of thrombosis.

A hormone called melatonin is secreted by the brain during the hours of darkness, and sunlight exposure suppresses melatonin production, so getting out into the sun enhances readjustment to local timings.

Sun-seeking is worth considering if travelling west - although one needs to beware of flash-frying and sunburn. On easterly journeys of five to nine hours, avoid evening light (use sunglasses or stay indoors) but seek out daylight in the late morning and early afternoon.

Melatonin is available over-the-counter in the US as a dietary supplement, and for those weekending in New York this might be worth putting on the shopping list. It is taken at bedtime: 3-5mg for three or four nights, and it can be used with prescription sleeping tablets. Melatonin not only helps alleviate jet lag but itself causes somnolence, indeed it is now used in the UK by paediatricians treating intractable insomnia in children, which reminds me to suggest that an important strategy in avoiding post-trip fatigue is to leave the kids with the grandparents.

Finally, some evidence suggests that high-protein breakfasts and high-carbohydrate dinners aid readjustment once home.

Dr Jane Wilson-Howarth is author of "Bugs, Bites and Bowels" and co-author of "Your Child Abroad". Melatonin is available on mail order from PharmWest (freephone 00800-8923 8923; www.PharmWest.com).