Deep Vein Thrombosis (DVT)

What you should know


Deep Vein Thrombosis (DVT)

This is a condition where clots of blood form in the deep veins of the calves. These clots can then spread to the lungs, which may be fatal. The risk is predominantly on long- sector flights (eg. Melbourne-London).
Despite the low risk of DVT for most individuals, there has been much media interest in this disorder. Although it has been dubbed “Economy-class Syndrome” there is no scientific evidence indicating that it is related to seating position.

Who is at risk?

The risk of clots forming occurs when blood pools in the calves of travellers who are immobile and dehydrated and who sit for extended periods of time (hours) in cramped conditions with low air humidity.
Risk may be increased in the following: history of DVT, recent surgery or injury especially to lower limbs or abdomen, blood disorders leading to increased clotting tendency, estrogen hormone therapy, including the oral contraceptive, pregnancy, tobacco smoking, former or current malignant disease, obesity, heart failure, varicose veins. The incidence of problems is greater in the older traveller.

How to decrease the chance of developing DVT

  • Short-sector flights, and long-sector flights with overnight stopovers are considered low-risk
  • Wear loose, comfortable clothing
  • Avoid sleeping tablets if possible as these further reduce body movements
  • Make sure you wiggle your toes at least every 15 min and have a stroll every hour; airlines generally publish in-flight exercise programs in their magazines
  • Do not consume excessive amounts of tea, coffee or alcohol
  • Drink plenty of water or fruit juice: in excess of 1 litre during a 10 hour flight
  • If you think you may be a higher risk individual (see above) seek medical advice before flying.


Preventative strategies may include use of aspirin, injections of the anti-clotting, heparin and elastic compression stockings. Stockings can be purchased from surgical supply companies and will need to be individually fitted to your leg measurements.

SEEK URGENT MEDICAL ADVICE if during the flight or after your arrival you develop swelling or pain in the calves of the legs; shortness of breath, chest pain; a cough with blood production.

Reference : Centres for Disease Control and Prevention. CDC Yellow Book 2020: Health Information for International Travel. New York: Oxford University Press; 2017.

*For more detailed information, make an appointment at our travel health clinic and our travel health professionals will be more than happy to discuss your personal needs.