The Connection Between Air Travel and Blood Clots

Long-distance air travel increases a person’s odds of developing blood clots, a condition known medically as venous thromboembolism (VTE) and dubbed in the media as the “economy-class syndrome.”

But choosing coach for your next vacation isn’t the problem per se. Inactivity is the culprit – the latest reports show that you’re more likely to get a blood clot sitting in a window seat and never making it to the aisle than from simply lacking legroom in economy class.

So how much risk does flying really pose and what can you do to lower your risk of blood clots the next time you jet off?

According to a recent summary published by Dr. John Bartholomew of the Cleveland Clinic, taking a long-haul flight makes you three times more likely to get a blood clot, but each year only about three in 1,000 travelers – or 0.3% – develop a blood clot following air travel. Less than two in a million develop “pulmonary embolism” after an eight hour flight. Pulmonary embolism is the more serious form of VTE that occurs when the clot breaks free, travels through the bloodstream, and blocks an artery in the lungs.

It’s particularly important to realize that most cases of air travel-related VTE occur in individuals who are already at increased risk for VTE based on genetic and/or non-genetic factors. Also, the association between air travel and VTE is strongest if the flight is longer than eight to 10 hours, though taking multiple, shorter duration flights within a short period of time can also pose some risk.

You can lower your odds of getting a blood clot by gauging your risk based on genetic and non-genetic factors (see below). There are also preventive measures you can take on long-distance flights. Perform stretching exercises while in your seat and periodically walk around the cabin on flights longer than four hours. If you are already at increased risk due to genetic and/or non-genetic factors, speak with your physician about preventive measures including compression socks and/or anticoagulant drugs.

Important VTE Risk Factors to Gauge Before Long-Haul Flights

  • Recurrent or prior history of VTE.
  • Family history of VTE.
  • Known clotting disorder.
  • Myeloproliferative disorders.
  • Cancer and chemotherapy treatment.
  • Major surgery in the weeks before flying.
  • Bedridden for multiple, consecutive days prior to flying.
  • Immobility including non-removable full leg casts and braces.
  • Pregnancy or recent delivery.
  • Estrogen use, including oral contraceptives.
  • Obesity.
  • Advanced age.