Harvard University researchers found that those who travel are three times more likely to develop life-threatening VTE, which are blood clots in a vein, usually found in the legs.
"Our findings demonstrate for the first time a clear association between travel and VTE," the researchers said in their report, published in the Annals of Internal Medicine.
VTE can be fatal if the blood clot travels to the lungs. Symptoms of the condition include swelling, pain and redness in the leg, or legs.
The study found the threat of developing VTE is not limited to air travel.
The researchers also show a measurable increase in the condition for every two hours sitting in a car. The research shows the longer the trip, the greater the threat of VTE.
The study suggests the situation is serious enough for more research to be carried out into how to keep travelers healthy, but not serious enough to justify giving airline passengers anti-clotting drugs.
"Worldwide, 2.5 billion people will travel by air alone in 2010, which underscores the large global population at risk for this serious condition," the researchers wrote.
They said drinking extra fluids and getting up and moving every two hours or so helps ward off the condition.
The condition is known as venous thromboembolism.
Report by David Wilkening
