Move Around on Long Flights to Prevent Blood Clots A new study shows that 1 in 4,500 travelers — particularly those who take long flights and fly often — will develop a blood clot. Although not every traveler has the same risk, doctors and even some airlines suggest staying alert and moving around in-flight.
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Move Around on Long Flights to Prevent Blood Clots

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Move Around on Long Flights to Prevent Blood Clots

Move Around on Long Flights to Prevent Blood Clots

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It's MORNING EDITION from NPR News. I'm Steve Inskeep.


And I'm Renee Montagne.

In Your Health today, a warning involving blood clots and airplane travel. If your travel plans call for a long airplane flight - say to Europe or Asia -experts have some advise to help cut the risk of developing of a blood clot.

New research from the World Health Organization shows that about 1 in 4,500 travelers will develop a clot. They're most likely caused by the combination of low air pressure on board and passengers not moving around enough.

NPR's Allison Aubrey reports.

ALLISON AUBREY: The classic struggle of airplane travel is the cramp factor. Bleary-eyed Ming Jong, who's just flown into Dulles airport after a 13-hour economy class ride from Korea, says she's definitely feeling it.

Ms. MING JONG (Commuter): It's too small to move around, so I couldn't. So I just crushed my body like a...

AUBREY: Jong curls up to show how she sat with her legs folded into her chest. Her friend Adam Nord, who is well over 6 feet tall, says after many uncomfortable flights, he feels her pain.

Mr. ADAM NORD (Commuter): I could barely move my knee up and down two inches behind the seat, so I kind of prefer to get up and walk up and down the aisles.

AUBREY: The importance of moving around in-flight is highlighted by a new report from the World Health Organization, based on two big studies. It shows that travelers who take long flights - more than four hours in length - face a two to three-fold increase in the risk of developing a blood clot.

John Heit, a hematologist at the Mayo Clinic, says this risk is nothing to panic over. The number of clots is still quite small, but he says blood clots can be dangerous.

Dr. JOHN HEIT (Hematologist, Mayo Clinic): Well, when most people think of blood clots, they think of clots in arteries, like an artery to the muscle of the heart or an artery to the brain that would cause either a heart attack or a stroke.

AUBREY: But what we're talking about here, he says, is completely different. These blood clots form deep inside the legs, so they're called deep vein thromboses, or DVTs for short. A lack of movement such as after surgery or long trips in a plane or car increase the likelihood of them. They get serious because the blood from these veins feeds back up into the lungs.

Dr. HEIT: And so if these clots dislodge, they travel to the lungs, which is termed pulmonary embolism, and that is potentially fatal. In fact, about 20 to 25 percent of patients suffer sudden death.

AUBREY: The sudden death of a young woman flying between Australia and Great Britain back in 2000 led to new research aimed at understanding exactly who's at risk of these clots. The WHO study found that about 1 in 4,500 airline passengers will develop this kind of clot. But not every traveler has the same risk.

Lead researcher Fritz Rosendahl of Leiden University in the Netherlands says, for instance, women who are taking birth control pills or hormone therapy and are severely overweight face a 30-fold increased risk. People who've just had surgery or fractured their leg are at increased risk, too.

Professor FRITZ ROSENDAHL (Leiden University, Netherlands): Businessmen who fly very often, within a short period of time, like say five times within three months - that's an additional three-fold increased risk.

AUBREY: And the risks stack up. Travelers who know they're at a higher risk can wear compression stockings. Unlike conventional hose, these stockings compress from the ankle up to encourage blood flow. And researchers say the step every traveler should take on long flights is to move. To make this possible in the confines of an economy class seat, Northwest Airlines introduces its trans-continental passengers to these flight attendants who are dressed in exercise clothes.

(Soundbite of in-flight video)

LISA: Hi, I'm Lisa, and I'm here with Denise, (unintelligible) and Karen.

AUBREY: During a short video, the flight attendants demonstrate a simple technique to promote circulation.

(Soundbite of in-flight video)

LISA: Now sit up straight with your hands at your side and with your feet together. Extend both legs out in front of you, lifting your heels up the floor just a few inches.

AUBREY: Passengers are told to flex their toes and then point them.

(Soundbite of in-flight video)

LISA: One more time, breath, point and then flex.

AUBREY: As simple as it sounds, Mayo Clinic John Heit says this is what he does when he flies, and it's really all that's needed.

Dr. HEIT: It keeps the blood moving in the veins, and that lowers the predisposition for the blood to clot. So at this point, that's the most useful recommendation.

AUBREY: Moving your legs about every two hours is the general advice. And researchers Fritz Rosendahl says in order to do this, people really need to be awake. Catnaps, he says, are okay, but...

Professor ROSENDAHL: People should not get into a really deep sleep. I think that's not a good idea.

AUBREY: So that means keep alcohol consumption to a minimum. And Rosendahl advises leave the sleeping pills at home.

Allison Aubrey, NPR News.

MONTAGNE: You can find a list of what puts you at risk of getting a blood clot while flying at There, you'll also find answers to listener questions for an entirely different story about how mothers can strengthen their relationships with their daughters.

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