Deep vein thrombosis and air travel

There is community concern that air travel may increase the risk of deep vein thrombosis (DVT). This page explains what DVT is, and provides a set of guidelines for the safety and comfort of air travellers.

Page last updated: 14 November 2003


There has been growing media and community concern that air travel may increase the risk of deep vein thrombosis (DVT). The Department has recently completed a research project to assess the scale of any such risk. This project was funded by the Department of Transport and Regional Services.

A summary of the results is provided at:


Immobility, Travel and DVT

DVT is a common medical condition in the population. The disease process in DVT occurs because of blood clotting, most frequently in the large veins of the calves. Sometimes these clots break free and travel up the veins through the heart to lodge in the arteries of the lungs. This related condition is known as pulmonary embolism (PE), and it may cause sharp chest pain or breathlessness. PE may be life-threatening if the embolus (circulating clot) is large.

DVT occurs most frequently among people who are immobilised. For example, the condition has been long recognised as a risk for people confined to bed. Immobility for even short periods can cause DVT. For this reason, preventive measures are frequently taken when people, particularly the elderly, undergo surgical operations, where they are immobilised by a general anaesthetic.
Travel by any mode of transport usually requires immobility, for some if not all of the journey. It is not therefore surprising that travellers occasionally experience the condition of DVT, with some later developing PE. A term that has appeared both in the media and the scientific literature is "traveller's thrombosis".

Each year in Australia there are up to 400 deaths from PE. Of these, only a very small number appear to be associated with air travel. Many occur in association with identified risk factors for DVT, which include increasing age, obesity, smoking, pregnancy, the use of oral contraceptives or hormone replacement therapy, cancer, lower limb injury or surgery, family history of DVT, and previous thrombosis or embolism.

  • The following recommendations for air travellers are based on a recent statement by The Australasian Society of Thrombosis and Haemostasis:
  • Drink plenty of (non-alcoholic) fluids during flights
  • Regularly mobilise the ankles and massage the calves
  • Wear loose, non-restrictive clothing
  • Avoid excessive movement around the cabin, as the risk of injury from turbulence may outweigh the benefit of exercise
  • Be vigilant for the symptoms of DVT, in particular pain in the calves, during and for up to a month after long flights. If symptoms occur, seek medical advice without delay.
The airlines are now making similar information available on the risk and prevention of DVT. If in doubt, people should obtain medical advice before travel, particularly if they have any of the identified risk factors for DVT.

Further reading

Gallus A, Baker R. Economy class syndrome: A misnomer for a syndrome for which the evidence is, as yet, missing. Medical Journal of Australia 2001; 174: 264-265.

Further information on DVT and air travel can be found on the Department of Foreign Affairs and Trade (DFAT) website.
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