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Whilst every effort has been made to ensure that the information contained on this site is accurate, it is not a substitute for medical advice or treatment, and Mr A. Abu-Own recommends consultation with a doctor or healthcare professional. The information provided is intended to support patients, not to provide personal medical advice.  Please see our Terms and Conditions for more information.

Thrombosis and Travel

Who is this information for?

This page contains general information on how to reduce the risk of a deep vein thrombosis (DVT) occurring during a long journey. Even if you aren't flying but plan to spend more than four hours on a train, bus, or car, then you should take precautions to help reduce your risks of getting a DVT.

How big is the risk while travelling?

Although there has been a lot of media attention around DVT, there has been marked variation in incidence between different studies. The longer the flight, the more likely you are to develop a DVT. It has to be stressed that the vast majority of travellers have no problems. Other risk factors are involved, so for most people the risk of developing a DVT just from a long journey is quite small.
To reduce the risk of travel-related DVT, you should take some simple precautions as a DVT can be dangerous. There is a chance that the blood clot in the leg can break up, travel through the body and get lodged in the lungs causing a life threatening condition called pulmonary embolism.

How can I reduce the risk of travel related DVT?

  • Exercise your calf muscles regularly:
    • Every half hour or so, do a few simple exercises while you are seated. Some good ones include ankle circling, tiptoe positioning and toe lifting while keeping your heels on the ground (reverse of tiptoe positioning). This will help to increase the blood flow in your legs.
    • Take a walk up and down the aisle every hour or so, when the seatbelt signs are not switched on or when you are starting a new journey.
    • Make sure you have as much space as possible in front of you for your legs to move. So avoid having bags under the seat in front of you and recline your seat if possible.
    • Take all opportunities to get up to stretch your legs, when there are stops in your journey.​​
  • Do not drink too much alcohol, as it will dehydrate you.
  • Do not take sleeping tablets as they can result in you sleeping in an awkward position.
  • Drink plenty of water and stay well-hydrated.
  • Wear special medical stockings if they have been recommended to you by your doctor.
    • They work by applying extra pressure on the veins to aid blood flow up the legs.
    • There is evidence to suggest that compression stockings can help to prevent travel-related DVT in people who have a high to moderate risk.
    • You can buy them from pharmacies. Ask the pharmacist for advice about the right type. They need to be 'graduated compression' stockings, worn to the knee, with the correct amount of compression (class 1). If you are wearing them, you must make sure they are a good fit. If they don't fit properly, they can cause more harm than good.
    • Please note that stockings do not replace the need for regular exercises, but can be used to supplement them.​
  • ​Anticoagulants in select cases.
    • Individuals with a particularly high risk may be advised to have a heparin injection (e.g. Enoxaparin) before a long haul flight. Heparin is an anticoagulant that 'thins' the blood making it less likely to clot.
    • You should see your doctor before your journey to discuss this option in the following circumstances:
      • Have had moderate surgery in the previous six weeks. Please note that if you have had a hip or knee replacement, or other major surgery, within the previous three months, you should avoid long-haul flights altogether.
      • Have cancer which is being treated.
      • Have thrombophilia.

What are the warning signs of a DVT to look out for?

If you develop a painful swollen calf, unexpected shortness of breath or chest pain shortly after a long journey, then see a doctor urgently. Note: slight painless puffiness of feet and ankles is common after a long journey and is unlikely due to a DVT.