An airplane cabin is pretty much a crime against nature. At typical cruising altitudes, air pressure is equivalent to 6,000 to 8,000 feet above sea level—more challenging on the body than Denver, the mile-high city. The amount of oxygen in the blood is reduced and gases within the body expand, producing that familiar popping sensation in the ears. Prolonged immobility, especially when seated, can lead to pooling of blood in the legs and the development of a clot called deep-vein thrombosis. DVT has been dubbed economy-class syndrome, but it can find its way to the front of the plane.
Walks up and down the aisle are recommended on flights longer than four hours, as are stretches for the back, arms, and calves. If one is in an increased-risk category (older, obese, pregnant, a smoker, recuperating from surgery, or taking hormone medications), there are other options. One is compression stockings, which must be fitted properly so they don’t act like tourniquets and do more harm than good. There’s also an anticoagulant called fondaparinux (brand name: Arixtra), given by injection, which lasts about 24 hours. But note: “With an anticoagulant, if you were to hurt yourself, there would be an increase in bleeding,” says Richard Wenzel, M.D., chairman of internal medicine at Virginia Commonwealth University. “If you have an ulcer, you could bleed out on the plane.” His suggestion for reducing clotting risk: Take a baby aspirin before flying.