Philip J. Goscienski, M.D.
Deep vein thrombosis (DVT) is the medical term for the formation of blood clots in the large, internal veins of the legs. The popular term is economy class syndrome but that's dangerously misleading, and not because it doesn't happen to the folks flying in first-class. It can occur any time the legs are quite still for a couple of hours or more.
When you walk, the muscles in your legs "milk" blood back to the heart. That blood only goes in one direction — toward your heart — because there are valves in the veins that keep it from sloshing back and forth. Unlike arteries that carry blood outward from the heart, veins have almost no muscle and no pumping action of their own. Without leg action blood moves so slowly, especially when the body is slightly dehydrated, that clots may form.
Small clots are usually harmless and eventually dissolve on their own but large ones can be fatal. If a large clot breaks off and travels to the heart it can block the flow of blood to the lungs or cause the heart to fail.
Flying in economy class gets the headlines for several reasons. Not only is it hard to stretch your legs but a lot more people fly in the back than lounge in the front cabin. Traveling by car or train allows for more movement so there's less risk of clot formation.
Some persons have much greater risk, especially those with recent surgery in the pelvic area, back or legs. Pregnant women or persons with cancer face a greater risk and so do those with a prior history of leg clots.
The hospital is probably where most deep vein thromboses occur. Think of all the people with recent stroke, heart attack, leg or spine fracture or back surgery. If your surgeon hustled you out of bed soon after the anesthesia wore off it was to prevent this often-fatal post-operative complication.
Travelers ought to take a tip from surgeons: keep moving. That might be inconvenient for your seatmates when you're in the middle of the row but by making them move you might be helping them to avoid economy class syndrome. Do some toe-ups and shallow knee-bends while you're up.
Stay well-hydrated during the trip. Avoid alcohol; it will keep you too relaxed to get up. Take an aspirin before you leave home. Wear elastic compression stockings on any long journey.
Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at email@example.com.