For Patients

I'm traveling. What do I need to know about blood clots?

traffic imageThe risk for developing venous thromboembolism, VTE--blood clots known as deep vein thrombosis (DVT) and pulmonary embolism (PE)--increase with any form of lengthy immobility, including when seated for a prolonged period of time when traveling by car, bus, train or plane. 

While the overall incidence of travel-related VTE is thought to be low,  long-distance travel may increase blood clot risk by 2 to 4 times compared to short trips. In general, clotting risk increases with the length of travel time and with the addition of pre-existing risk factors (listed below).

Tips for reducing VTE risk while traveling

People can reduce their risk for developing a blood clot by taking simple precautions.  Stay as active as possible. If traveling by car, take frequent travel breaks to stop and stretch your legs.  If traveling by plane, train or bus:

  • Get up periodically to walk the aisle.
  • Choose an aisle seat when feasible so it is easier for you to get up and move around during your trip.
  • Store luggage in the overhead bin to provide more leg room to stretch. 
  • Do calf-muscle exercises at your seat.  Raise your heels, keeping your toes on the floor, then bring them down. Do this several times. Now raise and lower your toes several times. Repeat this every half an hour (more often if you like).
  • Wear comfortable clothing that doesn’t overly constrict the legs or waist.
  • Avoid sitting with legs crossed.

If you are at high-risk for developing VTE:

In addition to the above prevention measures, persons with pre-existing risk factors for developing blood clots may need extra prevention measures when traveling.  Risk is increased further for persons with:

  • a previous DVT or PE
  • age over 40 years
  • recent major surgery or major trauma (within last 3 months)
  • active cancer
  • pregnant or have recently given birth (within 4 months)
  • a leg cast or immobilizer
  • use estrogen containing birth control pills, patches, rings
  • use hormone replacement therapy
  • varicose veins in the legs
  • obesity (body mass index of 30 kg/m2 and above).
  • a clotting disorder (thrombophilia)

If you think you have a higher risk for developing VTE while traveling, talk to your doctor about appropriate prevention measures.   These may include:

  • Use of properly fitted graduated compression stockings.  (15-30 mm Hg pressure at the ankle)
  • Use of an anticoagulant (blood thinner) medication if at particularly high-risk.

Know the symptoms of DVT and PE

While the immobility of long travel may contribute to the formation of a blood clot, the symptoms of DVT or PE may not appear right away.  One should always be aware of the symptoms of DVT and PE, but be especially mindful in the weeks following a long trip. 

Deep Vein Thrombosis (DVT): 

Symptoms range from mild to severe; may involve the foot, ankle, calf, whole leg or arm. The classic symptoms are:

  • Pain
  • Swelling
  • Discoloration (bluish or reddish)
  • Warmth

A potentially life-threatening complication of deep vein thrombosis (DVT) is pulmonary embolism, often referred to as PE for short. A PE occurs when a blood clot breaks off, travels through the blood stream and lodges in the lung.

Pulmonary Embolism (PE):

A blood clot in the lungs.  The classic symptoms are:

  • Shortness of breath
  • Chest pain (may be worse with deep breath)
  • Unexplained cough (may cough up blood)
  • Unexplained rapid heart rate

Recently diagnosed with DVT or PE and wondering if it is ok to travel? 

plane photoSome experts recommend against airline travel during the first 4 weeks following deep vein thrombosis (DVT) or pulmonary embolism (PE). However, there is little scientific evidence to support this guidance.  Some data have indicated that the hypobaric (low pressure) condition in the airline cabin activates our clotting mechanism and that that is one of the reasons why people who fly long-distance have an increased risk for developing DVT and PE. However, whether that is truly of clinical relevance is not known. Since it is not fully known whether airline travel in the first few weeks after an acute DVT or PE is truly detrimental and should really be avoided, the recommendation to avoid air travel is more a cautious suggestion than a firm recommendation.

Are there official guidelines about the prevention of travel associated VTE? 

Yes. The American College of Chest Physician (ACCP) 2012 guidelines have the following recommendations regarding long-distance travel:

  • For long-distance travelers at increased risk of VTE (venous thromboembolism), frequent ambulation, calf muscle exercise, or sitting in an aisle seat if feasable is suggested, as well as wearing of properly fitted, below-knee graduated compression stockings (15-30 mm Hg pressure at the ankle). This includes individuals with:
    • previous clots
    • recent surgery or trauma
    • active cancer
    • pregnancy
    • estrogen use (with birth control methods or other hormonal therapy)
    • advanced age
    • limited mobility
    • severe obesity
    • or a known clotting disorder (thrombophilia)
  • ACCP 2012 suggests against the use of aspirin or blood thinners to prevent clots.


Additional resources about travel associated VTE

From Clot Connect,

From the CDC, information on preventing DVT/PE associated with travel:

For patients:

For clinicians: