Traveler's Thrombosis - My Family Travels

This report from an international panel of travel medicine specialists looks at Deep Vein Thrombosis and how to prevent it.

A press conference on the hot topic of “Economy Class Syndrome” was the hit with the leisure travel press at the 8th annual Conference of the International Society of Travel Medicine in 2003. Economy Class syndrome is not a complaint about peanuts and pretzels — it refers to the ailment known as Deep Vein Thrombosis: the growth of blood clots and other vascular disorders resulting from sitting in cramped positions for long periods of time. At its most severe, DVT can lead to a fatal pulmonary embolism.

According to studies done by Dr. Wolfgang Schobersberger, professor of intensive care medicine at the University of Innsbruck, Austria, there is a two- to four-fold increase in the risk on pulmonary embolism for passengers taking flights 5000 kms or more.

Might this be the reason behind the ailing airline industry’s move to increase seat pitch on long haul flights?  Announcing first that the syndrome should be properly called Traveler’s Thrombosis (read on), the researchers explained their fascinating study. 

With the cooperation of Austrian Airlines, Dr. Schobersberger’s team found 20 travel buffs who were willing to fly from Vienna to Washington DC wired to various medical machines.  With a medical history for each of the subjects at hand, the team collected blood samples from the passengers seated in first, business and economy classes, between the fifth and seventh hour of flight, and found that each was displaying an increase in blood coagulation which, though harmless to these subjects, could present a risk to people predisposed to vascular ailments. These symptoms persisted for 24 to 48 hours after the flight in travelers of every age group.

Second Test

Dr. Schobersberger’s team then did a second test with another group of 20 rabid travel bugs, who were willing to take a 10-hour bus ride on a luxury touring coach from Innsbruck to Rome under medical surveillance. After studying the blood samples from both groups of travelers, his study revealed:

  • Long haul flights or bus trips have the same effect on the vascular system.
  • Travelers who were predisposed to pulmonary embolism or deep vein thrombosis suffered no greater effect than those who had no tendencies to vascular disease.
  • Other environmental elements, such as the reduced humidity and high altitudes affecting fliers, did not play a crucial role in his findings.

His conclusion:  sitting in a cramped seat of any kind was the culprit behind all symptoms.

When you travel frequently to present research as a clinical professor of surgery at the University of Hawai’i in Honolulu, as Dr. Bo Eklof does, Traveler’s Thrombosis is always a concern. The research he presented supported similar findings:  Of the 1.5 billion people who fly annually, up to 10% will experience some level of blood clots in the legs.  He quoted an Italian study finding 2.7-6% of those tested after flying showed blood clotting in their legs. When Dr Eklof extended his study, he found that 36% of patients with blood clots in their legs also had pulmonary embolisms (blood clots in their lungs). 

He concluded that because an airplane cabin is pressurized to a level less than that at sea level, which would naturally affect passengers’ blood pressure, the entire flight experience was hazardous.  His results, unlike Dr. Schobersberger, found that passenger immobilization, the upright coach class seat position, hypoxia resulting from high altitudes, and dehydration were all to blame for Traveler’s Thrombosis.

Dr. Eklof suggests that until more information is available, all passengers wear compression stockings on long haul flights (see for information on Ames Walker support stockings), and that travelers at risk should discuss taking blood thinners- prior to long haul travel- with their physicians. Other prevention measures include performing leg flexing exercises and remaining hydrated while flying.

Families with travelers at risk of thrombosis may also be interested in reading more at, a website which tracks current medical studies and hundreds of blood clot injury cases related to air travel.


Dr. Bo Eklof’s Tips for Every Traveler

  • Drink fluids.
  • Move feet and legs at least once every hour.
  • Take deep slow breaths at regular intervals.

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