Deep vein thrombosis (DVT) is a blood clot in a deep vein, usually in a leg.
A DVT is dangerous because the clot can break loose, travel through the bloodstream, and block blood flow to the lungs (pulmonary embolism). Without treatment, this can be deadly.
Why does travel raise your risk of DVT?
Sitting still for 4 or more hours slows down the blood flow in your legs. This makes your blood more likely to clot. And for the next few weeks, your blood clot risk stays higher than normal.
Even if you are healthy and have a low risk of blood clots, a long flight or road trip raises your risk of DVT.
If you already have a risk of blood clots, prolonged sitting raises your risk even more. Things that can already be raising your risk for DVT include a past DVT or pulmonary embolism, a recent surgery or injury, a blood clotting disorder, and cancer. Things that pose a small risk of DVT include pregnancy, taking hormones for birth control, or hormone therapy.
How can you prevent DVT from travel?
During a long trip (such as 4 or more hours):
If you are traveling by car, stop every hour or so. Get out and walk around for a few minutes. If you are traveling by bus, train, or plane, get out of your seat and walk up and down the aisle every hour or so.
While you're sitting, raise and lower your toes, keeping your heels on the floor. Then raise and lower your heels, keeping your toes on the floor. Do this every 20 minutes.
Wear loose-fitting clothes that aren't tight around your waist or your legs.
If you already have a risk of blood clots, talk to your doctor before taking a long trip. Your doctor may want you to wear compression stockings.
When to call a doctor
For a few weeks after a long flight or trip, be alert for signs of a blood clot. A DVT needs treatment right away.
Call 911 or other emergency services if you:
Suddenly have shortness of breath and/or chest pain. Chest pain from a blood clot that travels to the lungs (pulmonary embolism) often gets worse with deep breathing.
Cough up blood.
Faint or lose consciousness.
Call your doctor right away if you have:
Swelling, warmth, or tenderness in the soft tissues of your leg.
Pain in your leg that gets worse when you stand or walk. This is especially important if there is also swelling or redness in your leg.
Agency for Healthcare Research and Quality (2008). Your Guide to Preventing and Treating Blood Clots (AHRQ Publication No. 08-0058-A). Rockville, MD: Agency for Healthcare Research and Quality. Also available online: http://www.ahrq.gov/consumer/bloodclots.htm.
Chandra D, et al. (2009). Travel and risk for venous thromboembolism: Meta-analysis. Annals of Internal Medicine, 151(3): 180â€“190.
Kahn SR, et al. (2012). Prevention of VTE in nonsurgical patients: Antithrombotic therapy and prevention of thrombosis, 9th ed. American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest, 141(2 Suppl): e195Sâ€“e226S. DOI: 10.1378/chest.11-2296. Accessed June 19, 2015.
U.S. Department of Health and Human Services (2008). The Surgeon General's call to action to prevent deep vein thrombosis and pulmonary embolism. Available online: http://www.surgeongeneral.gov/library/calls/deepvein/index.html.
ByHealthwise StaffPrimary Medical ReviewerAnne C. Poinier, MD - Internal MedicineE. Gregory Thompson, MD - Internal MedicineMartin J. Gabica, MD - Family MedicineAdam Husney, MD - Family MedicineSpecialist Medical ReviewerJeffrey S. Ginsberg, MD - Hematology