by The Thrifty Traveller

Created on: July 01, 2007

Don't just sit there on that long airplane ride - get up an exercise!

The World Health Organization is the latest agency to warn passengers about potentially-fatal blood clots that could form in the calves of their legs on long-haul flights of four hours or more.

The condition, called "deep vein thrombosis," increases rapidly for those who are immobile for long periods of time, like airline travellers. The United Nations agency estimates that, for every 6,000 passengers on long-haul flights, one will develop the condition. So for approximately every 25 commercial jets flying from, say, New York to London, one passenger will suffer from blood clots in their lower legs.

The formation of the blood clot itself is not the hazard, although it can cause pain and cramping in the calf muscles. The threat comes if the clot breaks free. It could easily travel to the lungs, causing a potentially-fatal pulmonary embolism.

Countering the problem is not difficult. Getting up from your seat for a short walk up and down the aisles every half hour or so is a big help, as is performing a few leg-stretching exercises in the open areas of aircraft near the emergency doors or washrooms. Even if you're sitting in your seat, simply stretching your legs and pointing your toes up as far as possible will stretch your calf muscles and help break up any developing clots.

The W.H.O. reports those most at risk are travellers over 6' 4" tall (193 cm) or under 5' 4" (162 cm), the idea being that those whose legs dangle, or those whose legs are severely cramped by the limited space between rows of seats, are less able to move their limbs freely while sitting in their seats.

Several medical conditions can also increase the odds of developing a deep vein thrombosis on long flights. While more research needs to be done to determine the precise impact on risks the organization says factors like obesity, genetic predisposition to blood clots, age, and the use of oral contraceptives seem to increase the threat of developing the clots. Many airlines suggest passengers in these high-risk groups consult their doctors for advice before taking a long-haul plane journey.

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