Blood Clots During Travel

CDC recommends making sure you are up to date with your COVID-19 vaccines before travel, which includes additional doses for individuals who are immunocompromised or booster doses when eligible. Follow all requirements and recommendations at each location during travel, and take steps to protect yourself and others. If you are traveling internationally, check the COVID-19 Travel Health Notice for your destination and visit the International Travel webpage for requirements and recommendations.


Some long-distance travelers are at risk for a dangerous condition called deep vein thrombosis (DVT). This condition occurs when a blood clot forms in a large vein. Part of the clot may break off and travel to the lungs, causing a sudden blockage of arteries in the lung. This is known as a pulmonary embolism (PE). These conditions are rare, but can be fatal, so it’s important to understand what causes them, how to know if you are at risk, and what steps you can take to prevent them.

DVT Risk

passengers on a plane

Almost anyone can have DVT, but if you’re traveling for a long time, such as on an international trip, you may be at increased risk. This is because DVT can be caused by sitting for a long time, potentially creating damage and slow blood flow in the veins of your legs. This increased risk more often occurs with air travel, where you’re in a small space and it’s hard to get up and move around. But DVT can also happen when you are traveling by bus, train, or car.

Most people who develop travel-associated DVT have other factors that increase their chance of developing a DVT, including the following:

  • A previous blood clot
  • Family history of blood clots
  • Known clotting disorder
  • Recent surgery, hospitalization, or injury
  • Use of estrogen-containing birth control or hormone replacement therapy
  • Current or recent pregnancy
  • Older age (risk increases with age)
  • Obesity
  • Active cancer (or undergoing chemotherapy)
  • • Other serious illnesses, including congestive heart failure or inflammatory bowel disease
  • Limited movement

Preventing DVT

deep vein thrombosis animation

Anyone traveling more than 4 hours by air, by car, or by bus can be at risk for blood clots.

You can take steps to help prevent DVT. For long distance travelers, these steps include

  • Get up occasionally and walk around.
    • Select an aisle seat when possible so you can walk around every 2-3 hours.
    • If traveling by car, include breaks in your travel schedule to stretch and walk around.
  • Exercise your calf muscles and stretch your legs while you're sitting. Try these exercises next time you travel:
    • Raise and lower your heels while keeping your toes on the floor.
    • Raise and lower your toes while keeping your heels on the floor.
    • Tighten and release your leg muscles.

If you are a long-distance traveler with additional factors that increase your chance for developing a DVT, talk to your doctor about taking extra precautions, such as

  • Wearing properly fitted medical compression stockings and
  • Taking medication before you travel to prevent blood clots.

Symptoms, Diagnosis, and Treatment

It is helpful to know the symptoms so you can recognize if you develop DVT or PE.

DVT Symptoms
  • Swelling, pain, or tenderness in the affected limb (usually the leg)
  • Unexplained pain or tenderness
  • Skin that is red and warm to the touch
PE Symptoms
  • Difficulty breathing
  • Faster than normal heartbeat
  • Chest pain that usually gets worse when you cough or breathe deeply
  • Coughing up blood
  • Very low blood pressure, lightheadedness or fainting

If you have symptoms of DVT, call a doctor right away. If you have symptoms of PE, you should seek immediate medical care from a doctor or hospital. Finding and treating these conditions early can prevent death or complications.

It is not possible to diagnose either condition without special tests performed by a doctor to look for clots within veins in the legs, pelvis, and chest, and within arteries in the lungs, such as an ultrasound, a CT scan, or an MRI. That is why it is important for you to quickly seek medical care if you experience symptoms of DVT or PE.

DVT and PE are treatable, although a large PE can cause sudden death. Sometimes medicines or devices are used to dissolve or break up the clot. Typically, medicines are taken for several weeks or months to prevent more clots from forming and to give the body a chance to dissolve or heal existing clots.

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