Jet Lag

What is jet lag?

Jet lag is the fatigue you may feel after flying across several time zones. The rapid travel disturbs your normal body rhythms.

How does it occur?

Each person has an internal body clock that determines when sleeping, waking, and hunger occur in a 24-hour period. When you travel across several time zones, your "day" is longer or shorter than 24 hours. Your body is out of sync with the local time zone. Your normal body rhythms cannot adjust quickly to this shorter or longer day, which results in jet lag.

Not all jet lags are the same. Traveling eastward, which shortens your day, is more difficult than flying westward, which lengthens it.

What are the symptoms?

The symptoms of jet lag may include:

tiredness
drowsiness during the day
trouble sleeping at night
dulling of mental ability and memory
irritability
headaches
stomachaches
minor coordination problems and reduced physical activity.

How long will the effects of jet lag last?

West-to-east trips may require 1 day of recovery for each time zone crossed. East-to-west journeys may require 1 day of recovery for each one and a half time zones crossed. For example, when you cross 3 time zones flying east, it might take 3 days to recover, but when you fly west, it may take no more than 2 days for your body to catch up.

The adjustment can be eased by breaking up a long journey with a stopover. If you have an important event or meeting to attend at your destination, try to get there 2 or 3 days early.

What can be done to help prevent jet lag?

The following can help reduce the symptoms of jet lag:

Drink lots of beverages during the flight, but avoid those containing caffeine or alcohol.
Eat high-protein, low-calorie meals just before, during, and just after your flight.
If you fly east, you should go to bed earlier than usual for a few days before the trip. If you fly west, go to bed later than usual.
Schedule your arrival at about your usual bedtime, according to the time at your destination, or sleep on the plane and plan to arrive at your usual waking time.
Set your watch to the destination time when you are halfway through your flight, so you can start thinking in terms of the new time.
Spend more time outside at your destination. This exposure to bright outdoor light will help you to adjust faster than if you stay in your hotel room.

How do I adjust medicines prescribed for a certain hour?

If you are diabetic and use long-acting insulin, you may have to change to regular insulin until you have adjusted to the time, food, and activity of your destination.

You may have to adjust other medicine schedules according to the actual hours between doses rather than the local time at your destination.

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

HIA File GEN4442F.HTM Release 9.0/2006