Blood clots are also known as deep vein thrombosis (DVT), and can be a serious risk for someone travelling long-distance, this is according to the American Society of Hematology.

Over 300 million people travel on long-distance flights annually, so a journey of four hours or more and these people are at risk of developing a blood clot. 

Warning signs of blood clots are:

  • Swelling of the leg, ankle, or calf
  • Redness or discolour
  • Increased warmth over the skin
Blood clot, computer artwork.

In some cases, blood clots can dissolve and go away by themselves, however, there’s a potential that DVT can break off and travel to the blood vessels in the lungs, causing a pulmonary embolism (PE).


  • High blood pressure
  • High cholesterol
  • Use of oral contraceptives
  • Pregnancy
  • Certain cancers
  • Certain recent surgeries
  • Age (increased risk for people over age 40)
  • Obesity
  • History of previous blood clots
  • Family history of blood clots
  • Smoking
  • Trauma
  • Diabetes

How can you prevent blood clots from happening when travelling?

There are some simple steps you can take such as stretching your legs and changing sitting positions. If you’re choosing your seat before a flight, choose an aisle seat so you can stretch and walk around the plane every few hours.

If you’re prone to blood clots you should let the airline know before the flight, either by ringing them or letting the crew know when you get on the plane, so you’ll be looked after.

You can also,

  • Avoid drinking too much alcohol as it dehydrates you.
  • Wear the correct size of special medical stockings, otherwise they can cause more harm.
  • Avoid sleeping tablets as they can result in you sleeping in an awkward position and moving less.
  • Drink plenty of water.

If you feel you’re at risk of developing a blood clot on a flight you could talk to your doctor about the risks and prevention.

Depending on your physical condition, genetics and medical history, you could see a hematologist, a doctor who specialises in blood conditions. The doctor may recommend taking a blood thinner (orally or injection) prior to your flight.

If you’re concerned pay a visit to your own GP.

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