Introduction

Our bodies adjust to a natural rhythm that promotes sleeping at night and being active and alert during daylight hours. When we travel across differing time zones our normal rhythm is altered.

The sleep disturbance and loss of ability to concentrate, as well as the irritability felt during that time is called jet lag.

Time zones

The earth is divided into 24time zones, with time changing by one hour for every 150 of travel east or west of the Greenwich meridian. Travelling from London to New York necessitates turning your watch back by five hours, whilst traveling to Japan entails turning your watch forward by nine hours (nine time zones). Hence arriving in Tokyo by plane from London at bedtime your body will feel as though it is lunchtime. It takes time (about one day per-time zone crossed) to adjust to local time.

Sign & Symptoms

Sleep disturbance, loss of ability to concentrate, as well as irritability felt.

Complication

In untreated cases, rapid dehydration, acidosis, circulatory collapse, hypoglycemia and renal failure. Death may occur within few hours due to dehydration leading to circulatory collapse.

Treatment

Discuss with your doctor the possible benefits of a mild sleeping tablet for 2-3 days whilst you adjust.

Melatonin is used frequently in the USA. Taking the drug is advised just before bedtime. Avoid driving after taking the drug.

Hypnotics e.g. Temazepam help sleep and correspondingly alertness during following day.

Prevention & Precautions

In order to cope with jet lag;

• You should get a good sleep before your journey.
• Rest as much as possible during flight.
• Eat light meals and limit consumption of alcohol and caffeine. Drink plenty of water or fruit juices.
• Planning to arrive at your destination as near to the time when you normally go to sleep
• Changing watches to destination time when they get onto the plane. For those who are on regular medication such as diabetics, watches should remain on home time until you are able to adjust your medication to local times on arrival at your destination or as suggested by your health advisor.
• On arrival at your destination get active as soon as possible and adjust your meals and activities to local time as soon as you can.
• If you arrive at the evening, have a light dinner and go to bed late. Next day try to eat and sleep according to the local time
• If you arrive in the morning, stay active during day and get as much exposure to natural light as possible. Avoid heavy commitments on first day.

References organisation/ support

International Travel & Health, WHO 2006

http://travelhealth.co.uk/