In occupational medicine, there is such a thing as "economy class syndrome". Its essence lies in the fact that during the flight in economy class mobility feet (and whole body) is minimized. This, in turn, is a major cause of deep venous thrombosis.
When a person is in a state for a long time motionless, blood flow through the veins of the legs slows dramatically, which creates the risk of thrombus formation, even in healthy people. That it was formed, just enough to 1, 5-2 hours. However, this can be avoided if to prepare for the flight and follow the simple instructions.
When ordering tickets book your place in the front row at the exit, partitions or in the aisle. There's a bit more space that will allow you to stretch your legs or get up from the chair and some exercise.
Take an aspirin before the flight. It prevents the formation of a thrombus. If for any reason aspirin is contraindicated, it is possible to use tea with lemon. It is desirable in large quantities. This drink thins the blood and prevents it from forming clots. In other words - to clot.
Put in a special plane compression hosiery: stockings, pantyhose or stockings that improve blood flow through the veins. They can be purchased at the pharmacy. If it was not possible to get such a jersey, you should use elastic stockings or tights most dense that you have. It is not so much effective as in the case of compression hosiery, but it is still better than nothing.
Every 20-30 minutes to do exercises for the legs, in order to disperse the blood vessels. To do this you need to take off our shoes and 20 times the pull and squeeze your toes. Movement of these are not visible to public view, but perfectly stimulate the venous circulation.