Jet flight leg has been attributed to passengers having to sit still for long periods and is usually treated by massaging and moving the legs. But in a letter to the Lancet medical journal, Sam Shuster suggests that the cause of the swelling is the low air pressure in the cabin.
Professor Shuster, a fellow of Newcastle University, said that oedema [swelling] is most common amongst those with varicose veins and women over 30. It is usually noticed about three hours into the flight and varies from a slight ankle pitting to swelling of the lower leg.
He explains that if blood pressure remains unchanged but the pressure in the cabin is low then it will "suck" fluid out of the capillaries, creating swelling. "I have found the elastic compression stockings prevent the swellings completely in those with recurrent moderate or severe jet flight leg," he said.
"The stockings need only be lightweight, below the knee and above the toe, but must be put on before the flight."