Travel Health Information Sheets

Travel-related deep vein thrombosis


What is a deep vein thrombosis?

A deep vein thrombosis (DVT) is a blood clot in one of your body’s deep veins, usually in the lower leg. This can be dangerous and potentially fatal, if part of the clot breaks off and travels to your lungs.

A DVT can follow any period of inactivity, for example after an operation, but can also happen spontaneously in healthy people.

DVT has occurred after long flights and this has sometimes been called “economy class syndrome”. However, this is misleading, as DVT has also been diagnosed following long road and train trips; doctors prefer to talk about “travel-related DVT”.

What are the symptoms?

  • Pain, swelling and a heavy feeling in one of your legs. The area can be red and painful to touch. This often occurs at the back of your calf, below the knee.

  • If the vein gets completely blocked, your leg will get dark and swollen.


A serious complication of DVT is a clot in the lungs, called a pulmonary embolism. This occurs when part of the DVT clot breaks off and travels to your lungs. This is extremely dangerous and can kill you.

Getting very short of breath (difficulty in breathing) is the most common symptom of a pulmonary embolism.

Other symptoms are:

  • Chest pain

  • Coughing up blood

  • Sudden collapse

If you experience any symptoms of either a DVT or a pulmonary embolism, you must seek immediate emergency medical treatment.

What is my risk?

Research has found that DVT risk is similar after air, bus, car, and train trips. The risk is higher with longer journeys, particularly those over four hours and if you have certain health problems.

Thus, any lengthy inactivity, including long trips, puts you at risk. However, any of the following also increases your chance of developing a DVT:

  • A history of DVT or a pulmonary embolism - if you or anyone in your family has ever had a DVT or clot in the past.

  • Any recent surgery or operation, but especially hip and knee replacements.

  • A broken leg in plaster, as this restricts your movement.

  • Being very overweight.

  • Blood disorders that make your blood more prone to clotting.

  • Being over sixty, especially if you have problems with mobility.

  • Cancer and certain types of cancer treatment like chemotherapy.

  • Circulation problems or if you have had a stroke.

  • Dehydration.

  • Heart problems such as heart failure.

  • Hormone replacement therapy (HRT) or combined hormonal contraception, like the pill and contraceptive skin patches.

  • Inflammatory illnesses like rheumatoid arthritis.

  • If you are a pregnant or have just had a baby.

  • Smoking.

Can a DVT be treated?

Yes and the main aim of treatment is to stop a DVT from developing into a pulmonary embolism. Anyone with a suspected DVT should be admitted to hospital. Treatment to reduce blood clotting, usually with injections of an anticoagulant (anti-clotting) drug called heparin and/or tablets called warfarin is started immediately. Warfarin is usually prescribed for several months following a DVT, under careful medical supervision, which includes regular blood tests. You also need to wear properly fitted elastic compression stockings.

How do I reduce my risk?

  • Get advice from your doctor or specialist as soon as possible if you have a medical condition that increases your risk. You may need to be prescribed heparin injections to thin your blood and help prevent clots.

  • Stop smoking

  • Try to maintain a healthy weight.

During your journey:

  • Avoid dehydration: drink plenty of non-alcoholic fluids.

  • Do not wear restrictive clothes, especially around your waist or lower legs.

  • Get advice about properly fitted compression socks for long trips from your GP or pharmacist

  • Regularly flex and extend your ankles to encourage blood flow.

  • Store luggage in lockers or luggage compartments, rather than at your feet, to avoid restricting leg movement.

  • Take frequent deep breaths.

  • Try to walk around as much as possible.

Compression stockings

If you have an increased risk of DVT, you should consider using properly fitted below knee gratuated compression stockings providing 15 to 30mmHg of pressure at the ankle. It is essential compression stockings are correctly measured and properly fitted by a trained health professional (e.g. a nurse, midwife or pharmacist) as badly fitting stockings can increase your risk of DVT.



In some cases, heparin injections (see treatment section above) are given to try and prevent DVT during travel. If you are at increased risk, heparin thins your blood and reduces your risk of a blood clot. However, it cannot be given to everyone and your GP should discuss the suitability of prescribing this drug with a doctor specialising in blood problems. If heparin is suitable, your GP or nurse will advise you when to start (and stop) taking it, discuss any potential side effects and show you (and if appropriate, a travelling companion) how to inject it correctly.


Taking aspirin to try and prevent DVT is NOT recommended by doctors. There is no proof to show that it works and there is a risk of stomach irritation.


NHS Choices: Deep Vein Thrombosis

Last Reviewed November 2011

Last Edited December 2013

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