The study, published this week in The Lancet medical journal, found tiny clots in the calf veins of about 10 percent of passengers who flew for more than eight hours. However, the body makes and dissolves clots routinely and none of the clots in the study progressed to become a problem. Reports of passengers dying from clots after long flights have mounted recently, leading to speculation that the flights could be to blame. It may be that sitting in front of your computer for hours does the same thing. Experts estimate that every year, about one in a thousand people is diagnosed with blood clots in leg veins.
Clots occur when circulation slows, usually when people stay still for too long.
This is really about a change in our habits. The finding that 10 percent of the passengers developed a detectable clot may sound alarming, but experts said screening often picks up clots that prove to be harmless. Killer clots, where the clot breaks off, travels to the lung and blocks the flow of blood, are very rare. Blood clots show up on ultrasounds in about 50 percent of surgical patients, but only about 10 percent of those people go on to develop a meaningful clot, said Dr. Robert McBane of the Mayo Clinic. The Lancet findings should be viewed with that in mind, said McBane, who was not involved with the research.