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Blood clots and long trips

Immobility can have serious consequences. In the case of air travel, the prolonged immobility forced on passengers during flights of four, five or ten hours can cause a potentially deadly blood clot, the Centers for Disease Control (CDC) tell us. While any trip over four hours in length by car, train, bus or airplane can cause a deep vein thrombosis, airline passengers have the least mobility and are at greatest risk.

 Economy seats are seen in the Airbus A380, a double-decker plane flown by Lufthansa
Photo by Mario Tama/Getty Images

A deep vein thrombosis (DVT), according to the National Heart, Lung and Blood Institute, is a blood clot that forms deep in a muscle in the body. Most are found in the lower leg or thigh. A DVT is a potentially life-threatening condition that requires immediate medical attention.

The American Society of Hematology calls the occurrence of DVT while traveling by air "economy class syndrome." Passenger overcrowding and prolonged immobility force blood to pool in the lower legs. Pooling increases the risk of clot development due to the lack of sufficient blood circulation. The longer the flight, the greater the risk with flights of eight hours or more creating the greatest risk for a DVT.

Symptoms of a DVT, the CDC states, include swelling in the affected limb, unexplained pain or tenderness, a warmth to the skin in the area and a noticeable redness. The danger of a DVT lies in the potential for part of the clot to detach and travel through the circulatory system to the lung. Lodged in the lung, a clot is called a pulmonary embolism.

A pulmonary embolism is described by the U.S. National Library of Medicine as "a sudden blockage in a lung artery." It can cause permanent damage to the lung. Symptoms can include chest pain, trouble breathing, fainting or loss of consciousness, a fast or abnormal heart beat or coughing up blood. A large enough PE or multiple small PEs can be fatal.

Preventing a travel-related deep vein thrombosis is easily done. Stand up and walk around when you can. Ask your physician if graduated compression stockings would be useful. The website myDr.com.au provides a series of exercises that can be done while seated to improve blood flow to the lower legs.

Most DVTs will heal without complication. The treating physician can advise the patient on types of activities that can be done during the healing process. The doctor can also determine if there is any further risk of DVT in the future.