American Society of Hematology

Clots &Travel

Blood clots can sometimes form in your legs during air travel because you are immobile for long periods of time, often sitting in cramped spaces with little leg room. While commonly referred to as "economy class syndrome," the clinical term for this type of blood clot is deep-vein thrombosis (DVT). The longer the flight, the more at risk you are for developing a clot. Flights lasting 8-10 hours or longer pose the greatest risk.

In many cases, the blood clot will dissolve and go away on its own. However, in more serious cases, a blood clot formed in the deep veins of your leg may detach and travel to your lungs, causing a pulmonary embolism (PE).

DVT and PE, collectively known as venous thromboembolism, are highly preventable (see prevention tips below). The U.S. Surgeon General has issued a Call to Action on DVT and PE to raise public awareness of these blood conditions and increase research on the causes, prevention, and treatment.

There are several symptoms that can be warning signs of blood clots, including the following:

  • Swelling of the leg, ankle, or calf
  • Redness or discoloration
  • Increased warmth over the skin

Am I At Risk?

Your risk of developing a blood clot during air travel is increased by the following:

  • Use of oral contraceptives
  • Pregnancy
  • Cancer
  • Recent surgery
  • Older age
  • Obesity
  • History of previous blood clots
  • Genetic predisposition to blood clots
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How Can I Prevent Blood Clots When I Travel?

There are some simple steps you can take to avoid developing a blood clot while flying. Make sure to stretch your legs and get some exercise. You can do this by walking around the plane every few hours and changing positions in your seat. Also, drink lots of fluids and wear loose-fitting clothes that do not restrict blood flow and make it easier to move around.

Other tips include:

  • Avoid drinking alcoholic beverages the night before traveling and during travel
  • Store your carry-on baggage in a place that will allow enough leg room
  • Try not to cross your legs
  • Wear compression stockings

If you plan on traveling soon and have concerns about getting a blood clot, talk with your doctor about your risks and prevention. Depending on your physical condition, genetics, and medical history, you may want to see a hematologist, a doctor who specializes in blood conditions.

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Deep Vein Thrombosis: A Patient's Journey

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Where Can I Find More Information?

If you find that you are interested in learning more about blood diseases and disorders, here are a few other resources that may be of some help:

Results of Clinical Studies Published in Blood

Search Blood, the official journal of ASH, for the results of the latest blood research. While recent articles generally require a subscriber login, patients interested in viewing an access-controlled article in Blood may obtain a copy by e-mailing a request to the Blood Publishing Office.

Patient Groups

A list of Web links to patient groups and other organizations that provide information.

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