Wiggle Your Toes, Save Your Life

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Airlines are telling passengers on long flights to do more than just buckle up and stow their carryons in the overhead bins. In videos and public service announcements, they're urging them to wiggle their toes, stretch their legs and do other in-flight exercises that can prevent dangerous blood clots.

Sitting for a long time without moving can slow blood flow and cause clots in the legs, a condition known as deep-vein thrombosis (DVT). Most clots are small and disappear on their own. But if they break away and travel to the lung, they can create blockages—or pulmonary embolisms—that stop the supply of oxygen to the heart.

DVT can affect anyone immobilized for prolonged periods: bus drivers, car passengers, patients in hospitals. But the condition has become so associated with cramped airliner seats with little leg room, that it's called "economy-class syndrome." (In fact, first-class passengers get DVT, too—leading to speculation that low cabin pressure and humidity may be involved.)

Recent studies indicate that up to 20 percent of passengers on long-haul flights get a mild case of deep-vein thrombosis. About one in 100 develops serious symptoms, according to a recent study in the British journal The Lancet. As it has become apparent that flight-related DVT is not limited to old legs and old veins, the World Health Organization and other medical groups are taking a closer look. A 28-year-old woman from Wales, for example, died of a pulmonary embolism in 2000, soon after a 15-hour flight from Australia to London.

"An international flight in itself can be sufficient time for a blood clot to form in an otherwise healthy individual,'' says Robert Foronjy, a pulmonologist at New York-Presbyterian Hospital. More than 600,000 Americans a year get DVT, the American Heart Association reports. At least 60,000 die from pulmonary embolisms.

WHO'S AT RISK?

Going to Iraq to cover the war last year proved fatal for NBC correspondent David Bloom. He didn't die from combat injuries but from a clot in his lung.

The 39-year-old journalist had holed up in tight quarters for hours on end, first on a plane and then in a cramped armored Army vehicle he filled with broadcasting equipment. His problem began, as it does in nine of 10 cases of pulmonary embolisms, as deep-vein thrombosis.

Bloom showed no signs of vulnerability to DVT before going to Iraq. But some conditions can increase risk, such as major leg injuries, varicose veins or hip or knee replacements. "Leg veins have little valves that prevent blood from going backward, away from the heart," Foronjy says. "If valves are damaged, blood pools in the legs."

Obesity, heart disease, cancer, high blood pressure, major surgery, heavy smoking, hormone replacement therapy and birth control pills also increase the risk of clots.

Older people are affected more often than younger people. "To make matters worse," Foronjy says, "the elderly have less lung function, so a large obstruction there places them at an increased risk of dying."

ON THE LOOKOUT FOR DVT

The signs to watch for include persistent cramping, swelling, redness and pain in the legs, chest pain and shortness of breath. Travelers may have symptoms immediately, or not for hours or even days. Sometimes they may not have them at all.

If DVT is suspected, prompt treatment is crucial. "At least 10 percent of people with pulmonary embolisms die within the first hour," Foronjy says. Only 3 percent of those who get treatment die.

Bloom took aspirin for a painful cramp in his leg, according to a Business Week report. But aspirin does not work once a clot has formed. "It's too weak," Foronjy says.

DVT is treated with anticoagulant drugs such as heparin or warfarin (Coumadin) to impede clot formation. If internal bleeding occurs, a metal mesh filter may be inserted surgically below the heart to catch clots.

Clot-busting drugs, such as tissue plasminogen activator (tPA), can break up embolisms. In some cases, surgery may be required.

Michele Meyer is a freelance health writer living in Texas.