What is a deep vein thrombosis?

Also known as traveler’s thrombosis, DVT is the development of a blood clot, usually in the lower leg, that decreases or completely blocks blood flow through the vein. Often caused by prolonged periods of immobility, a blood clot that forms in the leg can break free and move to the heart, lungs or brain.

What are the risk factors for developing DVT?

There are a number of factors that can increase your chances of developing a blood clot, including being older than 40 and having a history of stroke or heart disease. Other risk factors include recent surgery (especially in the abdomen or legs), taking estrogen such as that contained in birth control pills, smoking, pregnancy, liver disease, previous DVT or family history of DVT, varicose veins, heart failure, obesity and immobility.

As a frequent traveler,am I more at risk for developing DVT?

It is well documented that DVT can occur in people who sit in cramped positions for long periods of time. For that reason, airline passengers and pilots are at risk for DVT, sometimes called economy-class syndrome. Medical studies suggest the risk of developing DVT may increase for people who are frequent passengers on long-haul flights. In addition to cramped quarters, airline passengers are also subject to possible dehydration and to cabin pressure changes that could exacerbate the condition. Incidents of DVT related to air travel are difficult to track, but estimates suggest approximately one in 100 frequent long-haul travelers may develop DVT. DVT can also occur as a result of immobility during long automobile trips.

What are the symptoms of DVT?

Symptoms of DVT include pain, swelling or discoloration in legs or calves that does not improve. You may also feel a pins-andneedles sensation that does not go away and may have difficulty bearing weight on the legs. If you experience these symptoms, see a physician immediately. You should also seek medical attention directly if you develop shortness of breath or chest pain during or after prolonged travel. Those symptoms could indicate a pulmonary embolism, meaning a portion of a clot may have traveled to your lungs where it is occluding the blood supply. This is a serious condition that could lead to death.

How can I prevent or limit the possibility of developing DVT?

Keep moving and avoid prolonged sitting. Get up and walk around to stretch your legs every hour, if possible. Avoid dehydration by drinking a glass of water or juice at least every two hours. Avoid alcohol and caffeine. Do leg-stretching exercises while seated or standing for long periods. Frequent stretching will make your muscles more relaxed and prevent pooling of blood in the legs.

Simple stretching exercises include foot flexions and extensions. When sitting in your seat, bend your feet upward with toes spread, hold for a count of five seconds, then point your feet downward and clench your toes for five seconds. Perform ankle rotations by moving your ankles in circles, and stretch your calves. Try to do a set of these stretches 10 times every hour. Do not cross your legs or sit on the edge of your seat since these positions can reduce blood flow to your legs. Elevate your legs when possible. Wear comfortable and nonrestrictive clothing while traveling. If you have a history of blood clots or other risk factors, see your doctor before you go. Compression stockings can improve circulation, but should only be worn with a physician’s approval. Your doctor may also suggest taking an anticoagulant, such as aspirin, prior to long-haul travel. Taking folic acid or vitamin E are other measures worth discussing with your physician.

Request an exit row, bulkhead or aisle seat where you’ll have more room to stretch your legs. Many airlines post information about DVT on their Web sites or in brochures available at the check-in counter. Some carriers, including Singapore Airlines, British Airlines and Australia’s two major airlines, do an excellent job communicating information about DVT to the traveling public.

For more information about deep vein thrombosis, visit the National Institutes for Health Web site at www.nih.org