Do You Know about Blood Clots and Travel?
Blood clots can be a serious risk for anyone traveling more than four hours. Learn how to prevent dangerous blood clots.
People love to travel. For example, more than 300 million people travel on long-distance airline flights (generally more than four hours) each year.1 But did you know that blood clots, also called deep vein thrombosis (DVT), can be a serious risk for some long-distance travelers. Most information about blood clots and long-distance travel comes from information that has been gathered about air travel. However, anyone traveling more than four hours, whether by air, car, bus, or train, can be at risk for blood clots.
Blood clots can form in the deep veins (veins below the surface that are not visible through the skin) of your legs during travel because you are sitting still in a confined space for long periods of time. The longer you don't move around, the greater is your risk of developing a blood clot. A serious health problem can occur when a part of the blood clot breaks off and travels to the lungs causing a blockage. This is called a pulmonary embolism, or PE, and it may result in death. The good news is there are things you can do to protect your health and reduce your risk for blood clots during a long-distance trip.
Are You at Risk?
Even if you travel a long distance, the risk of developing a blood clot is very small. Your level of risk depends on the length of travel as well as whether you have any other risks for blood clots. Most people who get blood clots during travel have one or more other risks for blood clots, such as:
- Older age (risk increases after age 40)
- Obesity (body mass index [BMI] greater than 30 kg/m2)
- Recent surgery or injury (within 3 months)
- Use of estrogen-containing contraceptives (for example, birth control pills, rings, patches)
- Hormone replacement therapy (medical treatment in which hormones are given to reduce the effects of menopause)
- Pregnancy and the period after birth (up to 6 weeks after childbirth)
- Previous blood clot or a family history of blood clots
- Active cancer or recent cancer treatment
- Limited movement (for example, a leg cast)
- Catheter placed in a large vein
- Varicose veins
CDC Expert Commentary
Blood Clots and Long Distance Travel: Advising Patients
View this video to learn more about how healthcare providers can advise their patients on long-distance travel and blood clots.
The combination of long-distance travel with one or more of these risks may increase your chance of getting a blood clot. The more risks you have, the greater your chances of getting a blood clot. If you plan on traveling soon, talk with your doctor to learn more about what you can do to protect your health. The most important thing you can do is to learn and recognize the signs and symptoms of blood clots.
Know the Signs and Symptoms
Deep Vein Thrombosis (DVT) (blood clot in the leg, arm, or other deep vein)
About half of people with DVT have no symptoms at all. The following are the most common symptoms of DVT that occur in the affected part of the body (usually the leg or arm):
- Swelling of your leg or arm
- Pain or tenderness that you can't explain
- Skin that is warm to the touch
- Redness of the skin
If you have any of these symptoms, call your doctor as soon as possible.
Pulmonary Embolism (PE) (blood clot in the lungs)
You can have a PE without any symptoms of a DVT. Symptoms of a PE can include:
- Difficulty breathing
- Faster than normal or irregular heartbeat
- Chest pain or discomfort, which usually worsens with a deep breath or coughing
- Coughing up blood
- Lightheadedness, or fainting
If you have any of these symptoms, seek medical help right away.
Protect Yourself and Reduce Your Risk
- Know what to look for. Be alert to the signs and symptoms of blood clots.
- Move your legs often when on long trips and exercise your calf muscles to improve the flow of blood. If you've been sitting for a long time, get up and stretch your legs. Extend your legs straight out and flex your ankles (pulling your toes toward you). Some airlines suggest pulling each knee up toward the chest and holding it there with your hands on your lower leg for 15 seconds, and repeat up to 10 times. These types of activities help to improve the flow of blood in your legs.
- Talk with your doctor if you think you may be at risk for blood clots. If you have had a previous blood clot, or if a family member has a history of blood clots or an inherited clotting disorder, talk with your doctor to learn more about your individual risks.
- If you are at risk, talk with your doctor to learn more about how to prevent blood clots. For example, some people may benefit by wearing graduated compression stockings.
- If you are on blood thinners, also known as anticoagulants (medicines to prevent blood clots), be sure to take the medication according to your doctor's instructions.
Amaris's Personal Story
My name is Amaris White and I want to share my personal experience with blood clots. My hope is that by sharing this information, you will learn the signs and symptoms of this potentially fatal condition and know how to protect yourself and others.
In 2012 I was an active and healthy 25-year-old. I had run two half-marathons during the past year, and I was traveling for a month with friends to Southeast Asia to celebrate my successful completion of the bar exam.
We had been traveling for a few weeks when my lower back started to ache. I didn't think much of it and ignored it for a week, chalking it off to the uncomfortable hostel beds. On our last night in Kuala Lumpur, Malaysia, my leg started to swell and within a few hours the pain and swelling were so severe that I could no longer walk. My left leg became discolored and for the next two days my roommate and I went to different hospitals in Malaysia in order to get a diagnosis—all the while my leg grew progressively darker, the pain increasingly crippling. I had a difficult time getting a diagnosis, but ultimately I was able to have my leg and foot examined through Doppler ultrasound. These test results confirmed that I had deep vein thrombosis (DVT), a condition in which a blood clot develops in a deep vein in the body. Continue reading Amaris's story...
- Gavish I, Brenner B. Air travel and the risk of thromboembolism. Intern Emerg Med 2011 Apr;6(2):113-6.
- Page last reviewed: August 4, 2014
- Page last updated: March 24, 2014
- Content source:
- National Center on Birth Defects and Developmental Disabilities, Division of Blood Disorders
- Page maintained by: Office of the Associate Director for Communication, Digital Media Branch, Division of Public Affairs