The study appears in the Journal of the American Medical Association saying that the clotting changes were probably the result of sitting still for eight hours.
The researchers have also advised travelers to stretch their legs, extend and flex the knees and ankles, and stand and walk whenever possible.
Simon Snedden, one of the key researchers, told The Voice of America, "Any form of long-haul travel, whether by air, rail, or road is associated with an increased risk of thrombosis. People should take sensible precautions according to their level of inherent risk."
