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Medical Author:

John P. Cunha, DO, FACOEP

John P. Cunha, DO, FACOEP

John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.

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Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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In this Article

• What is jet lag?
• What are other symptoms and signs of jet lag?
• What is a time zone?
• Why does jet lag occur?
• How does the body keep time?
• What is the role of melatonin in jet lag?
• Does the direction of travel matter?
• Do the symptoms of jet lag vary in intensity?
• How long does jet lag last?
• What are the best ways to cope with jet lag?
• Should I take melatonin?
• Patient Comments: Jet Lag - Remedies
• Patient Comments: Jet Lag - Symptoms
• Jet Lag Index

Yes. Travelers flying north or south in the same time zone typically experience the fewest problems because the time of day always remains the same as in the place where the flight originated. These travelers may experience discomfort, but this usually results from confinement in an airplane for a long time or from differences in climate, culture, and diet at the destination location. Time differences do not play a role.

Travelers flying east, on the other hand, typically experience the most problems because they "lose" time. For example, on an international flight from Washington, D.C., to Mecca, Saudi Arabia, a traveler loses eight hours. Meals, sleep, bowel habits, and other daily routines are all pushed ahead eight hours.

Travelers flying west "gain" time and usually have an easier time adjusting than eastward travelers. However, they too experience symptoms of jet lag after landing because they still must adjust to a different schedule.

Yes. People flying across only one or two time zones may be able to adjust without noticeable effects of the time change. Those flying across three or more time zones will likely develop noticeable symptoms of jet lag. Generally, the intensity of symptoms varies in relation to the number of time zones crossed and the direction of travel. People also vary in their susceptibility to jet lag symptoms and the severity of the symptoms.

Recovering from jet lag depends on the number of time zones crossed while traveling. In general, the body will adjust to the new time zone at the rate of one or two time zones per day. For example, if you crossed six time zones, the body will typically adjust to this time change in three to five days.