Thrombosis Australia

Thrombosis Australia is a central information and resource hub for the community proudly brought to you by the Perth Blood Institute



Our Thrombosis Australia Advisory Panel consists of eminent Australian healthcare professionals.

Thrombosis Australia Advisory Panel

If you are a healthcare professional you can access the Thrombosis Australia Professionals site here:

Thrombosis Australia Professionals


Why does travel increase your risk of a DVT?

Thrombosis – a clot in your veins or arteries - can occur while you are traveling. In fact, long-distance travel can increase your risk of developing thrombosis. This risk is higher for those traveling more than 4 hours at a time. While many DVTs are symptomless and cause no further complications, they are potentially life threatening – so being aware of the risk and preventing them is important. It is especially important for people already at risk of developing DVTs to be aware of the added risk of long-distance travel.

Long-distance travel increases your risk of developing thrombosis by two to three times(1)

Cramped seating and long periods of sitting can cause your blood to pool and form clots in your veins. Another reason is that the low oxygen and high-pressure conditions in an aeroplane dehydrate your body – which both contribute to the formation of clots.

The increased risk of a blood clot remains for up to 2 weeks after long-distance travel(1) 

Who is more at-risk of a DVT during travel?

Everyone – young, old, fit or unfit - is at risk of thrombosis during travel. Below is a list of factors that can increase your risk of developing a DVT:

Being unable to move around: 

  • Hospitalisation
  • Long-term bed rest
  • Paralysis
  • Long-term sitting - such as travel

Surgery and Injury:

  • Major injury - especially of the legs and lower body
  • Major surgery - especially of the hips and legs
  • Catheterisation

Other medical conditions:

  • Cancer and cancer treatment
  • Heart failure or heart disease
  • Thrombophilia (clotting disorder)
  • Obesity/overweight


  • Birth control which contains oestrogen
  • Hormone replacement therapy
  • Pregnancy and the 6 weeks following birth


  • Smoking
  • Family history of thrombosis
  • Age over 50 years
  • Varicose veins

If any of these risk factors apply to you it is important to discuss this with your doctor.

Can you reduce your risk of a DVT during travel?

  1. Wear compression stockings
    • Wearing compression stockings can reduce your risk by helping your blood flow from shallow to deep veins, increasing overall blood flow and reducing its ability to clot.
  2. Move around
    • Clots are more likely to form when you are stationary for a long time, so once every hour or so try to walk around. If you can’t walk around, learn the easy foot exercises below to help increase blood flow through your legs.

  1. Avoid crossing your legs or wearing clothes that are too tight
    • Crossing your legs and tight clothes restrict blood flow and cause your blood to pool where it is more likely to form a clot.
  2. Avoid alcohol
    • Alcohol will cause your body to become even more dehydrated than it already is during a flight. This will make blood clots more likely to form and increase your risk of a DVT.
  3. Stay hydrated!
    • Drinking plenty of water will allow your blood to flow more easily and help to prevent the formation of blood clots

What are the symptoms of a DVT?

If you are concerned about the possibility of developing thrombosis during travel, speak to your doctor about your risks and options.

For more information about thrombosis and its risk factors click here.                                                 

Travel and thrombosis FAQs:

Is it okay to travel after having a blood clot? How long should I sit at one time?

Yes – but try not to sit for more than an hour at a time. Every hour get up and walk around whenever it is safe or perform seated exercises for several minutes. If you have had a DVT you might consider wearing compression stockings, wear loose fitted clothing, avoid alcohol, and stay hydrated. Your doctor might suggest taking blood-thinners if you are traveling long-distance.

Should I use aspirin or anticoagulant medication on a long-haul flight?

Aspirin has been shown to have limited effectiveness in preventing DVT during long-distance flights. If you have never experienced a DVT and are at low-risk for experiencing one, utilising the tips above will help to prevent thrombosis during long-distance travel. 

If you have an inherited thrombophilia or have a history of DVT your doctor may recommend an anticoagulant such as low-molecular-weight heparin for the duration of your flight. Speak to your doctor about your risks and whether this is suitable for you. 

Can I drink alcohol?

Drinking alcohol on a long-distance flight can increase your risk of thrombosis. Avoiding alcohol, coffee, salty foods (things that will dehydrate you), and drinking plenty of water, will lower your chance of experiencing a DVT while on a long-distance flight.  

Should I wear stockings?

Compression stockings may be recommended by your doctor if you have an increased risk of developing thrombosis. Multiple studies have shown that wearing graduated compression stockings can reduce your risk of developing a DVT while on a long-distance flight. 

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  1. WHO Reserach Into Global Hazards of Travel (WRIGHT) Project. Final report of phase 1. Available at: 
  2. Clarke, M., Hopewell, S., Juszczak, E., Eisingam A., and Kjeldstrom, M. Compression stockings for preventing deep vein thrombosis in airline passengers. 2006. Cochrane Database Syst Rev. Apr 19;(2):CD004002

  3. Pai, M., and Douketis, J. Prevention of venous thromboembolism in adult travellers. 2019. UpToDate.