If you're travelling on a long-haul flight, there are several ways you can reduce your risk of getting deep vein thrombosis (DVT). Travel-related DVT was first reported in 1954 in a 54-year-old doctor who developed a blood clot following a 14-hour flight. The condition was soon dubbed "economy class syndrome" by researchers, who believed there was a link between long-haul air travel in cramped conditions and DVT. The actual number of people who get DVT on long-haul flights is unknown and is difficult to determine, as the condition can be symptomless and may not occur for some time after travel. However, there is some evidence to suggest that certain people, such as pregnant women or people who have had a stroke, are at increased risk of developing DVT on flights of eight hours or more.

What is DVT?

DVT is a medical condition which occurs when blood flows too slowly through the veins. The blood forms a clot that blocks up deep veins, usually in the legs, and may sometimes travel as far as to the heart.


DVT doesn’t generally have any immediate symptoms, making it difficult to spot. However, typical signs include a swollen or painful calf or thigh, paleness and increased heat around the affected area. If left untreated, people with DVT are at risk of developing a pulmonary embolism, when part of the blood clot breaks away and travels to the lung, which can be fatal. Before you travel if you think you have a high risk of developing DVT, see your doctor before you travel. You may be prescribed blood-thinning drugs to lessen the risk of your blood clotting, or compression stockings (also called flight socks). Studies have concluded that airline passengers who wear compression stockings during flights of four hours or more can significantly reduce their risk of DVT as well as leg swelling (oedema). The below-knee stockings apply gentle pressure to the ankle to help blood flow. They come in a variety of sizes and there are also different levels of compression. Class 1 stockings (exerting a pressure of 14–17 mmHg at the ankle) are generally sufficient. It’s vital that compression stockings are measured and worn correctly. Ill-fitting stockings could further increase the risk of DVT. Flight socks are available from pharmacies, airports and many retail outlets. Take advice on size and proper fitting from a health professional or pharmacist. DVT high-risk factors:

  • History of DVT or pulmonary embolism
  • Cancer
  • Stroke
  • Heart Disease
  • Inherited tendency to clot (thrombophilia)
  • Recent surgery (pelvic region or legs)
  • Obesity
  • Pregnancy
  • Hormone replacement therapy

Flight socks

  • Flight socks are recommended for people at high or moderate risk of DVT.
  • They should be worn throughout the flight.
  • Use below-knee graduated stockings with an appropriate compression.
  • Class 1 stockings (exerting a pressure of 14–17 mmHg at the ankle) are generally sufficient.
  • Get advice from a health professional (doctor, nurse or pharmacist) on correct size and fitting.

While you're travelling

  • Wear loose, comfortable clothes.
  • Consider buying flight socks (compression stockings).
  • Store luggage overhead so you have room to stretch out your legs.
  • Do anti-DVT exercises. Raise your heels, keeping your toes on the floor, then bring them down. Do this 10 times. Now raise and lower your toes 10 times. Do it at least every half an hour (you can do it more often if you like).
  • Walk around whenever you can.
  • Drink plenty of water.
  • Don’t drink alcohol or take sleeping pills