Flying can prove fatal in economy class

Air passengers are at much greater danger of developing fatal blood clots than previously thought, according to new research to be published later this year.

Air passengers are at much greater danger of developing fatal blood clots than previously thought, according to new research to be published later this year.

Cramped conditions and lengthy exposure to the reduced air pressure aboard planes could be responsible for more than 6,000 pulmonary embolism deaths a year.

Other life-threatening conditions such as deep vein thromboses and strokes have also been connected with what has become known as "economy class syndrome".

Scientists at the Aviation Health Institute, a medical research body that promotes the health and welfare of passengers, recruited 200 long-haul passengers in January to take part in their research.

Blood samples were taken from the volunteers, aged 50 and over, both before and after a plane journey of at least 10 hours in duration, and the changes in blood consistency and characteristics recorded.

Farrol Kahn, director of the Institute, said: "Most of the volunteers were found to have a marked increase in the thickness of the blood at the end of the flight which puts them at greater risk of a pulmonary embolism.

"Until now, this has been perceived as a problem for the elderly but our findings are demonstrating that this is also the case with younger people.

"One of the main explanations is the lack of humidity in an airline cabin which is a lot less than on the ground so passengers need to drink a lot of water.

"Many passengers do not realise that when they are sitting their blood circulation is cut by 50 per cent and so they should try to simulate a walking action in their seats to keep circulation going.

"The lack of oxygen also causes the surface of veins to wrinkle and this creates a greater likelihood of clotting.

"Blood clotting in victims of pulmonary embolism first occurs in the lower legs but many people show no symptoms until the clot reaches the lungs and causes them to collapse. We suggest that by taking an aspirin before they fly, passengers will help thin the blood and reduce the clotting risks."

The health risks associated with flying have also been expounded by Professor Peter Vanezis, a leading forensic pathologist, who at last week's Pathology 2000 conference in Birmingham accused airlines of putting profits before passenger's health.

Professor Vanezis, of Glasgow University, said: "The relationship between pulmonary embolism and flying is well-recognised but I think the documented cases are just the tip of the iceberg.

"Pulmonary embolism can hit the passenger days after their flight so it is usually very difficult to prove that flying is the cause.

"It seems to me that the airlines are herding most people into cramped seats in economy class for the sake of the few with more expensive tickets. I find this morally wrong given that there are these risks to health sitting in cramped aisles.

"On journeys of more than four or five hours I think they should get rid of some economy class seats and give us all some more space."

A spokesperson for British Airways, however, rejected the idea of reducing the number of cabin seats: "There's no evidence to suggest blood clots are linked to flying - the problem is prolonged immobility. Economy class syndrome is a misnomer as this is a problem for the entire transport industry.

"A lot depends on a passenger's lifestyle and previous medical history and our inflight magazines give passengers information about the importance of exercise on long flights."

The risk of blood clots will be one of the issues examined by a House of Lords inquiry, chaired by Baroness Wilcox, launched into the health affects of air travel earlier this month.

Peers will hear evidence from airlines, aircraft manufacturers, the medical profession and the government, and are expected to produce a report by the end of the year.