Vascular Surgeon
Expert in the treatment of varicose veins

I have to fly soon, is there a risk for my venous circulation? What can I do to prevent this?

I have to fly soon, is there a risk for my venous circulation?

The main risk of venous complication during a flight is venous thrombosis of the lower limbs, called phlebitis.

Phlebitis is the formation of a clot in a vein. In the legs, it can occur in the calf or thigh, up to the groin or even above in the pelvis.

It can be manifested by a swelling and/or pain in the calf (deep vein) or a sensitive redness of the skin (superficial vein). It can also be completely silent without any symptoms.

Phlebitis can be complicated by a pulmonary embolism due to the migration of the clot from the leg veins to the heart and lungs. This complication is rare but serious and even potentially fatal.

Why can air travel cause phlebitis?

Air travel involves venous risk factors:

  • Prolonged immobilization in a seated position, especially if the legs cannot be unfolded properly.
  • Limited possibility of walking.
  • Variation in atmospheric pressure equivalent to 2000 meters of altitude during the flight.
  • Dehydration due to the very low humidity in the airplane.

These risk factors have consequences that can lead to the formation of thrombus (clots in the leg veins) by slowing down venous circulation (lack of effective muscle contractions) and thickening of the blood (dehydration).

What can be done to prevent this risk?

The main means of prevention is to wear a venous compression, in the form of tights, stockings or socks This compression must be worn before boarding and maintained throughout the flight.

Other means of prevention are exercising that cause contraction of the calf muscles, such as walking of course, but also regular movements to stand or even sit on tiptoes. This activates the venous circulation in the legs (see blog on how the veins in the legs work).

In cases of high personal risk of phlebitis (see below), an anticoagulant treatment, in addition to wearing a venous compression, may be indicated and prescribed by a doctor, and generally administered by an injection a few hours before the flight.

Are some trips more risky than others?

Studies have shown that air travel lasting more than 4 hours is statistically more risky for venous disease than shorter trips.

It is therefore mainly long-haul flights that are risky for the veins.

However, if personal risk factors are present (see below), compression may be indicated even for short flights.

Apart from air travel, long car journeys are also at risk of phlebitis, especially if there are no regular stops.

Travel by train is less risky because of the smaller seating capacity and the greater possibilities of movement.

Are there any personal situations that increase the risk of venous disease when flying?

There are personal situations that increase the risk of phlebitis:

  • History of venous disease, phlebitis or pulmonary embolism
  • Known coagulation disorder
  • pregnancy
  • Recent surgery

In these situations, it is advisable to wear a venous compression device, even when traveling by plane with flights of less than 4 hours. An anticoagulant prescription may also be indicated for any prolonged seated travel in case of personal high risk factor.

The presence of respiratory insufficiency (history of pulmonary embolism, emphysema, chronic bronchitis) may also be considered as a risk situation because of the possible consequences of phlebitis complicated by pulmonary embolism.

What are the other venous risks?

Swelling of the feet, ankles or calves is common during air travel due to the inevitable slowing of venous circulation caused by prolonged sitting. This swelling corresponds to an edema.

Studies have shown that after 6 hours of flight time, almost all passengers have edema upon arrival at their destination.

This swelling may or may not be painful.

This swelling may or may not be painful. As with the prevention of phlebitis, wearing venous compression, moving the calves (tiptoeing) and walking are very effective in preventing these swellings.

Are some venous compression products better than others?

A medical compression product delivered on a doctor’s prescription, by a pharmacist or a specialized orthopedic store should be preferred, ideally of class 2 according to French standards.

Unlike medical products, there is no scientific proof of the effectiveness of products labeled “compression stockings” or “venous prevention” found in over-the-counter stores.

Tights, thigh-high stockings or knee-high socks are generally equally effective, since compression of the calf is essential, except in the case of varicose veins in the thigh or knee area, where thigh-high stockings or socks ending above the varicose veins should be preferred.

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