Jet lag

2009-02-26 14:12:07

Jet lag is a combination of fatigue and other symptoms caused by travelling abruptly across different time zones. Another name for jet lag is 'time zone change syndrome'. The body is synchronised to night and day by the action of sunlight through brain chemicals or neurotransmitters, especially melatonin. Many bodily processes are timed on this 24-hour physiological 'clock', such as temperature, hormones, digestion, heart rate, blood pressure and brain states. This changing rate of activity over each 24-hour period is called the circadian rhythm ('circadian' means approximately one day). Travelling to a different time zone disrupts the circadian rhythm. Other factors that contribute to jet lag include lost sleep. There is no cure for jet lag, but its effects can be reduced with careful planning.

Symptoms

The symptoms of jet lag include:

Flying east or west makes a difference

Your circadian rhythm (body clock) is less confused if you travel westward. This is because travelling west 'prolongs' the body clock's experience of its normal day-night cycle (the normal tendency of the body clock in most of us is slightly longer than 24 hours). Travelling eastwards, however, runs in direct opposition to the body clock. If you suffer badly from jet lag, it may be worthwhile considering a westerly travel route if possible.

Strategies while travelling

There is no evidence that popular strategies, such as fasting or eating complicated diets, have any effect. Suggestions to reduce the impact of jet lag while travelling include:

Sleeping on the plane

Suggestions include:

Adjusting to the new time zone

The internal body clock of a jet-lagged traveller is out of synchronisation with the new time zone, and is still operating on 'home time'. Different bodily processes adjust to the new time zone at different speeds, which adds to the confusion. Depending on the individual, the body needs anywhere from a few days to a few weeks to acclimatise to the new time zone.

Sleep and your new time zone

Suggestions on adjusting to your new time zone include:

Alcohol and medications

Using medication is controversial and should be discussed with your doctor. There have been reports of some benefits from either melatonin or very short-acting sedatives. It is not recommended that you use sleeping tablets during your flight in case of an emergency. Some travellers use alcohol to help them get to sleep, but this actually disrupts the normal sleep cycles and can prolong jet lag.

Where to get help

Things to remember