The Connection Between Air Travel and Blood Clots

Are you a jetsetter?

Long-distance air travel increases a person’s odds of developing a blood clot, 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 guaging 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. May be due to genetic factors including those reported in the 23andMe Venous Thromboembolism Established Research report.
  • 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.

View your results for more genetic factors linked to venous thromboembolism in your account.
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Editor’s note: Pending an FDA decision, 23andMe no longer offers new customers access to health reports referred to in this post. Customers who purchased prior to November 22, 2013 will still be able to see their health reports, but those who purchased after that time will not. Those customers will have access to ancestry information as well as access to their uninterpreted raw data.





  • Polly Hattemer

    A change in barometric pressure makes it more more likely that platelets will stick together and produce a blood clot. In this situation, peppermint helps to prevent the platelets from sticking together. Peppermint is also a remedy for motion sickness. Thus a little peppermint candy eaten during your next flight may help prevent the blood clots and motion sickness.

    This abstract says that when the barometric pressure lowers, it induces
    platelet aggregation — the platelets clump together. It also says that
    Japanese peppermint oil inhibits this aggregation.

    http://www.ncbi.nlm.nih.gov/pubmed/3715814

    Taurine may also be of some help here.

    Taurine stabilizes the platelets against aggregation. [1] At 400 mg per
    day, taurine reduced platelet aggregation by 30%, and at 1600 mg per
    day, taurine reduced platelet aggregation by 70%.

    1. Hayes, K.C., et al., “Taurine modulates platelet aggregation in cats
    and humans.” Am J Clin Nutr, 49(6) 1211-6, 1989 and Seelig M, MD, MPH
    “Magnesium taurate and fish oil for prevention of migraine. Med
    Hypotheses (ENGLAND) Dec 1996, 47 (6) p461-6

    Human platelet aggregation is induced by decompression or reduced
    barometric pressure, reduced hydrostatic pressure, and reduced
    hydrodynamic pressure due to Bernoulli’s principle, he spontaneous
    platelet aggregation induced by reduced barometric pressure is inhibited
    by 1:10 diluted Japanese herbal peppermint plant oil and by two of its
    major constituents, menthone and menthol.

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