dr-kc1Kevin R. Campbell, MD, Special to Everyday Health

During the holidays many Americans travel long distances to be with family and friends — this can mean prolonged sitting in cars and on buses, trains, or planes. You may not be aware that extensive travel can put you at risk for developing a particular type of blood clot known as a deep vein thrombosis or DVT.

Deep vein thrombosis is a condition in which a blood clot forms within deep-circulation blood vessels  — typically in the veins in the legs. Veins drain blood back to your heart so it can be oxygenated in the lungs. Blood clots often form when blood is allowed to pool in the extremities for long periods of time, such as with prolonged sitting or extended periods of lying in bed (for example, after surgery). Sitting still for more than four hours at one time can put you at increased risk for DVT. And after a period of prolonged sitting, your risk for forming a DVT may persist for several weeks.

Other risk factors for DVT include

  • prior blood clots
  • recent surgery
  • pregnancy
  • cancer
  • certain medicines such as oral contraceptives and hormone replacement medications

The American Heart Association estimates that 1 in 1000 people develop DVT each year. Symptoms of DVT include swelling, warmth or redness in the leg or calf. In some cases, patients develop pain in the calf that is worse when standing or walking. This is particularly alarming if it is associated with redness and swelling. DVTs may not be apparent right after travel but often appear after the trip is over and in the weeks following the trip.

Complications That Can Threaten Your Life

DVTs can be very serious. The most serious complications of DVT can be a pulmonary embolism, or PE. In the case of a PE, a piece of the blood clot in the vein can break off and travel to the lungs. If the clot lodges in the lungs it can prevent circulation through the lungs and even result in death if it's not treated quickly.

If you think you have developed a DVT you should seek medical help immediately. If you develop shortness or breath or chest pain with breathing you should call 911 and seek emergency help — this could indicate that the blood clot has traveled to the lungs and a pulmonary embolism has occurred.

Here are some simple tips to help prevent DVT during your holiday travel:

  1. If you're traveling by car, stop every hour and get out and walk around. If you're on a plane, try to get up and walk every 30 minutes, if possible
  2. Avoid alcohol, caffeine, and other substances that may cause dehydration. Drink plenty of fluids, preferably water.
  3. While sitting on the plane or in the car, try to raise your toes and flex your calves every 20 minutes. This motion causes your calf muscles to contract and promotes the flow of blood in the leg veins. This can help keep blood from pooling and forming a clot.
  4. If you have risk factors for DVT, you may want to consider talking with your physician before traveling to obtain compression stockings for your legs. If you have had a previous blood clot, you may need to take blood thinners.

Air and car travel are an essential part of the holidays for many of us, so it's important to be aware of the signs and symptoms of DVT and understand your risk.  By performing simple exercises when you're sitting and taking care to walk and stretch several times during your trip, you will have a better chance of avoiding this common travel-related malady.

Dr Kevin R. Campbell, is Assistant Professor of Medicine, Division of Cardiology, University of North Carolina at Chapel Hill and President, K-Roc Consulting LLC.