Broadcast: May 7, 2003
By Nancy Steinbach

This is the VOA Special English Health Report.
People who travel on long trips should know about a condition that can develop deep inside the legs. This condition is called deep vein thrombosis. A thrombosis is a blood clot, a condition where some blood thickens and blocks the flow. Clots develop in the legs when blood cannot move easily back to the heart. Doctors say this can happen when a person sits too long in one place.
Blood clots1 can kill if they move to the heart and lungs and cause what is known as a pulmonary embolism. Recently an American television reporter, David Bloom, died as he covered the war in Iraq. Medical experts believe a clot formed in his leg because he slept every night in a very small space inside a military vehicle.
Mister Bloom had felt pain behind the knee. Military doctors had urged him to seek treatment. Finally the clot moved to the artery2 leading to his lungs. Oxygen could no longer reach the heart.
Such blood clots are a risk for people who travel in airplanes, trains, motorcycles, buses and cars. Doctors say some people have an increased risk. These include people who have had clots in the past, as well as pregnant women and those who take birth control pills. People who are overweight and those with heart disease or cancer also may have a greater risk. Others include people being treated with estrogen3, and those who have had a recent operation.
The experts say the chances of a clot also increase if a person does not drink enough water. They say travelers who sit for hours should drink plenty of water--not liquids that contain alcohol or caffeine. Another thing to do is to increase the blood flow to the legs. This could mean wearing support stockings or taking an aspirin a few hours before the trip. Also, people should not sit for a long time with their knees pressed back against their seat. Walk around every hour or so. Or at least make sure to move the feet and legs.
Doctors say anyone who has pain, swelling or red skin on a leg during or after a long trip may have a blood clot. Signs that a clot may have already reached the lungs include chest pain, shortness of breath, coughing and a fast heart rate. Anyone with these signs should seek examination by a doctor immediately. In many cases, the condition can be treated with drugs that thin the blood and prevent clots from moving through the body.
This VOA Special English Health Report was written by Nancy Steinbach.
1． clot [klCt] n. （血液等的）凝块
2． artery [5a:t[rI] n. 动脉，要道
3． estrogen [5estr[dV[n] n. 雌激素