During the holidays, many of us travel long distances to be with family and friends, which can mean prolonged sitting in cars, buses, trains, or planes. You may not be aware that extensive travel, sitting still for more than four hours at one time, 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.

          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.

         In the video, Dr. Kirk Hance, a vascular surgeon at The University of Kansas Health System, explains the risks of developing a DVT while traveling. He explains how the length of the journey makes a difference, and how squeezed leg room can impact DVT. As for what travelers can do about it, he offers these tips:

• 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
• Avoid alcohol, caffeine, and other substances that may cause dehydration. Drink plenty of fluids, preferably water.
• 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.
• 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.