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Air travel and thrombosis

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Faraway destinations are popular with many people. A beautiful round trip through Australia or New Zealand, enjoying the temples in Asia, admiring nature in South America, these are all wonderful destinations that require a long flight. That means sitting still for hours on an aeroplane, sometimes with little legroom. This can cause venous or deep venous thrombosis (hereafter we will only call it thrombosis in this article).


What is thrombosis?

Thrombosis occurs when a blood clot forms in one or more deep veins of the body, usually in the legs. Thrombosis occurs when the coagulation and anticoagulation system is out of balance. There are substances in our blood that cause coagulation: if we have a wound, the body quickly makes a clot so that the bleeding stops. At that moment, the clotting also stops and any excess clot is broken down again. This keeps the system of coagulation and anticoagulation in balance. Thrombosis goes wrong in this system: the blood solidifies while there is no wound.


Risk factors for thrombosis

Known risk factors for thrombosis are:

  • long periods of sitting or lying still, for example in the event of illness or a flight of more than six hours;
  • use of the contraceptive pill;
  • pregnancy;
  • hereditary abnormalities in the blood;
  • operations;
  • atrial fibrillation (cardiac dysrhythmia);
  • cardiovascular diseases;
  • smoking;
  • not using an arm or leg for a long time due to a bone fracture.

The risk increases with the multiplication of factors. So, if you smoke, have a cardiovascular disease and have to sit in an aircraft seat for a long time, you are extra susceptible to thrombosis. It is then wise to discuss this with your GP prior to your flight.


Tips for preventing thrombosis on the plane

There are a number of ways to reduce the risk of thrombosis during a long flight:

  • Wear loose, easy-fitting clothing and loose-fitting shoes.
  • Move your legs and feet regularly during the flight, by sitting down or doing some exercises.
  • Make a “detour” in the plane every hour.
  • Wear compression stockings, but make sure they are properly fitted by a specialist. Too narrow stockings can cause thrombosis and too loose stockings have no function.
  • Drink a lot of water. Be economical with coffee and certainly do not use alcohol in the plane.
  • Do not use sedatives, as they reduce blood flow.

We always take off our shoes during the flight and keep our calf muscles and legs supple every half hour by doing a few small exercises. Besides that, we regularly walk “around the block” in the plane.


Symptoms of thrombosis

The following signals may indicate thrombosis:

  • swelling in the leg, ankle or foot;
  • pain in the calf that spreads to the ankle or foot;
  • heat in the affected area;
  • paler, redder or bluer skin.

In that case, it is wise to contact a doctor directly at your destination for a correct diagnosis and thrombosis treatment. Divers diagnosed with acute thrombosis or using anticoagulants should refrain from diving until a doctor has approved them for diving.