Jet lag is a common condition that sometimes occurs when you are flying long distances. It occurs because your body finds it difficult to adjust to a new time zone. Jet lag can disturb your sleep pattern, leaving you feeling lethargic and lacking in energy.
Time zones
The world is divided into 24 time zones. The Greenwich meridian (an imaginary line that passes through Greenwich, in London, and is used to help measure longitude) is the base. The time changes by one hour for every 15 degrees travelled in either direction from the Greenwich meridian.
Jet lag happens when you cross over a number of time zones and disrupt the body's normal "circadian rhythm", or "biological clock".
Your internal body clock controls when you need to sleep and when you are alert. It also affects hunger, digestion, bowel habits, urine production, body temperature and blood pressure. Your biological clock is normally synchronised with your local time so that you feel hungry in the morning and sleepy in the evening.
When you travel across time zones, your body needs time to adjust to a new daily routine.
Who gets jet lag?
Anyone can get jet lag, regardless of how frequently they travel by plane. People of any age can develop the condition, although it is more common in those over 50 years of age, and is relatively rare in children and babies.
Jet lag is not always inevitable when you are flying long distances, and there are ways that you can help prevent the condition from occurring (see "prevention" section).
Although jet lag may be problematic for people who have to fly frequently or who are travelling to an important meeting or event, it does not cause any serious or long-term health problems. Most people find that jet lag symptoms pass within a few days.
