What were they thinking?
A lot of people are interested in what they can do to reduce the risk of blood clots from flying. Considering that I’m spending a fair amount of time these days going back and forth between the US and UK, I was interested to see the recent news reports about a JAMA article (Effect of Hypobaric Hypoxia, Simulating Conditions During Long-Haul Air Travel, on coagulation, Fibrinolysis, Platelet Function, and Endothelial Activation), concluding that flying doesn’t cause blood clots. The Times of London, for example, had this to say:
Conditions particular to travelling on a long-haul flight, such as low air pressure and reduced oxygen, do not increase the risk of potentially lethal blood clots, research indicates.
But wait a minute, the study simulated the effects of reduced cabin pressure by putting participants in a hypobaric chamber. That’s one part of the picture –and nice for the airlines to know they can continue to get away with lower pressurization than is present at ground level–, but despite the fact that 13 authors collaborated on the study, it seems they neglected to examine the issues that are thought most likely to cause deep vein thrombosis: dehydration and sleeping while sitting.
Mickey told me he was disappointed that the researchers didn’t consider these more fundamental issues nor give practical advice. So what’s an air traveler to do, I asked Mickey. Here’s what he said:
My recommendation to people taking long flights is to stay well hydrated, avoid bending your knees far while sleeping, try to wake up enough to move your legs a bit many times during the flight, and consider taking one baby aspirin (81 mg) before starting the flight.
(Disclaimer: I’m not your doctor, and neither is Mickey. See [or email] your own for medical advice.)May 17, 2006