Avoiding jet lag Your body's biological clock can become desynchronised when you travel rapidly through several time zones. The resulting jet lag may affect your physical and mental performance.

To avoid jet lag disturbing the first few days of your holiday as your body acclimatises to a new time zone, you may need need to think ahead and synchronise your body clock before you travel.

If you're travelling east, try going to bed earlier for a couple of nights. If you're travelling west, go to bed later.

The following suggestions can also help to reduce the effects of jet lag.

• Drink plenty of water before, during and after the flight to avoid dehydration.
• Don't drink lots of alcohol or take unnecessary medication while in flight.
• Sleep well before the flight and during long journeys if you can.
• If you're travelling west over four or more time zones (to New York, for example) make sure you get bright natural light in the early evening. This will help you to adapt to the new time.
• If you're going east back to the UK, try to return at around midday to get the brightest light of the day. Wear eyeshades on the plane and try to stay in the dark and quiet.
• Exercise while on the plane. Don't just walk around the cabin - stretch in your chair as well. This will help your blood circulation and reduce swelling of the feet and legs.

This article was last medically reviewed by Dr Trisha Macnair in September 2006.
First published in May 2001.