Deep Vein Thrombosis (DVT’s) 2020-01-26T09:22:40-05:00

Traveling more than four hours at a time in an airplane, car, or other mode of transportation can increase your risk of developing a deep vein thrombosis (DVT, deep vein blood clot). Your susceptibility to DVT’s is based on the number of risk factors you have for DVT formation. If you are at higher than average risk for a DVT, there are steps you can take to decrease your chances of forming a clot.

DEEP VEINS and BLOOD CLOTS: There are deep veins in the arms and legs that are usually invisible because they are buried deep in tissue. Blood clots can form in these veins, more often in legs than arms. These clots can then occasionally break off and end up in one or both lungs. Rarely, the clots are large enough to significantly decrease the oxygen flowing into your bloodstream and can even stop blood from flowing through your lungs altogether, resulting in death.


  • Swelling (usually calf or thigh)
  • Pain or cramping of an affected limb
  • Redness and/or warmth of an affected limb
  • At least half of people with DVT’s have NO detectable symptoms or signs.


  • Shortness of breath
  • Cough (with or without blood in sputum)
  • Chest or back pain
  • Rapid heartbeat
  • Lightheadedness

AM I AT RISK? DVT’s due to extended travel are relatively uncommon. One study, for example, reported that the absolute risk of VTE for flights >4 hours is 1 in 4,656 flights (National Center for Biotechnology Information). Your level of risk depends upon how long your trip is, as well as whether you have any other risks for blood clots. Risks include:

  • Age over 40
  • Obesity
  • Recent surgery or injury (within 3 months)
  • Chronic Inflammatory Diseases (Lupus, Crohn’s, etc.)
  • Use of hormonal birth control (OCP’s)
  • Hormone replacement therapy
  • Pregnancy and up to 3 months after childbirth
  • Previous blood clot or a family history of blood clots
  • Active cancer or recent cancer treatment
  • Heart Failure
  • Limited mobility (for example, a leg cast)

If you have one of these risk factors and are traveling long-distances, you may have an increased chance of forming a deep vein thrombosis. The more risks you have, the greater your chances of experiencing such a blood clot.

CAN I DECREASE MY RISK? YES. If you have one or more of the risk factors listed above, you may be able to lower the chances of developing a blood clot.

  • Get up and move around frequently (every hour)
  • Performing calf exercises (flexing and extending your calf muscles)
  • Sit in an aisle seat
  • Staying hydrated
  • Avoiding alcohol

There is also data that shows wearing below-knee compression stockings (graduated compression stockings, GCS’s) decreases your risk. Much of the data on GCS’s relates to other situations, such as preventing clots after surgery and in very ill hospitalized patients. However, it is generally accepted that their benefit extends to long-distance travelers.

WHAT ABOUT BLOOD THINNERS? There are ongoing questions regarding whether the benefit of using aspirin, injectable blood thinners (for example, Lovenox), and blood thinner pills (coumadin, Eliquis, Pradaxa, etc.) for short periods of time before, during, and after long-distance travel outweighs the risk. For people at the highest risk of blood clots, the benefit of taking the medication may outweigh the risk.

Contact your medical provider if you have any questions regarding your DVT risk. We review this risk at our NY Travel Vaccine Clinic during your consultation. If you think you have suffered a DVT or pulmonary embolism, call your medical provider immediately or go to the nearest hospital.

For more information about DVT’s, see the Centers for Disease Control and Prevention

Have a safe trip!

Julian Klapowitz, MD

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