Jet lag is a condition in which a person's normal sleep cycle is disturbed by travel across time zones.
A person who travels between different time zones need time for his or her internal body clock to reset itself and adjust to the new time zone. The body usually develops a set pattern of times when it is used to eating, sleeping, working, and performing other activities. Jet lag occurs because the body is reacting to a change in the schedule of normal activities.
The primary cause of jet lag is crossing time zones and then trying to get the body to react and adjust right away. Flying north or south does not cause jet lag. The more time zones crossed, the more difficult it is for the body to adjust to the new time zone. The body can generally adjust to a time change of about 1 or 2 hours per day. After travel across three time zones, which often occurs in a trip from the west to the east coast, the body may need up to 3 days to adjust to the new time.
The common symptoms of jet lag include:
Most people will recognize when they have jet lag. The fatigue, drowsiness, irritability, and other symptoms will be clear to someone who has just traveled between different time zones.
Some measures may help prevent or lessen the severity of jet lag. These include:
There are no long term effects.
The only risk to others is when a person who is suffering from jet lag becomes unpleasant and uncomfortable to be around. Jet lag is not contagious.
There are no medical treatments for jet lag. Time will make jet lag disappear. When multiple time zones are crossed, such as in overseas travel, some people may want to use a mild sedative, sleeping pill, or melatonin to help "reset" their internal body clocks and get enough sleep.
Sedatives, such as diazepam, and sleeping pills, such as diphenhydramine, may cause prolonged sleepiness and may impair coordination. Melatonin may not work in some people and has caused sexual dysfunction in animals.
People gradually adjust to the new time zones and need no further treatment.
People can monitor their own symptoms of jet lag.
Editor:Smith, Elizabeth, BA
Reviewer:Adam Brochert, MD
Mayo Clinic Family Health Book, Second Edition, 1996, Published by William Morrow and Company, 1350 Ave. of the Americas, New York, NY 10019