Blood clots occur when blood flow is slowed or stopped. Flying on an airplane can increase your risk for blood clots, and you may need to avoid air travel for a period of time following the diagnosis of a clot.

Sitting still for extended periods of time can affect blood circulation and lead to the development of blood clots. Airplane flights of four hours or moreTrusted Source may be a risk factor for deep vein thrombosis (DVT) and pulmonary embolism (PE). DVT and PE are serious complications of blood clots that may be fatal in some cases.

DVT and PE can be prevented and treated in many cases, and there are things you can do on long flights to reduce your risk. Even people with a history of blood clots can enjoy airplane travel.

Read on to learn more about the connection between blood clots and flying, and what you can do to reduce your risk.

Flying with a blood clot or history of clots

If you have a history of blood clots or have recently been treated for them, your risk of developing a PE or DVT while flying may be elevated. Some medical professionals recommend waiting for four weeks after treatment is complete before taking to the air.

Your doctor will help determine if you should fly or if it makes sense to postpone your travel plans. Many factors will play into this decision, including:

  • your health history
  • the location and size of the clot
  • flight duration

Many factors outside of long air travel can increase your risk for blood clots, including:

  • personal history of blood clots
  • family history of blood clots
  • personal or family history of a genetic clotting disorder, such as factor V Leiden thrombophilia
  • being 40 or older
  • smoking cigarettes
  • having a body mass index (BMI) in the obese range
  • using estrogen-based contraception, such as birth control pills
  • taking hormone replacement medication (HRT)
  • having had a surgical procedure within the past three months
  • vein damage due to injury
  • current or recent pregnancy (six weeks post-delivery or recent loss of pregnancy)
  • having cancer or a history of cancer
  • having a vein catheter in a large vein
  • being in a leg cast


There are several steps you can take to help reduce your risk for blood clots while flying.

Prior to liftoff

Based on your health history, your doctor may recommend medical treatments to decrease your risk. These include taking a blood thinner, either orally or via injection, one-to-two hours prior to flight time.

If you are able to choose your seat before the flight, select an aisle or bulkhead seat, or pay an additional fee for a seat with extra leg room. That will help you stretch out and move around during the flight.

It’s also important to alert the airline that you are prone to blood clots and need to be able to move around the plane. Let them know prior to boarding the plane, either by calling the airline ahead of time or alerting the ground crew in the boarding area.

During the flight

During the flight, you’ll want to move around as much as possible and stay hydrated. Reiterate your need to move around freely to your flight attendant, and walk up and down the aisle for a few minutes every hour as permitted. If there’s a lot of turbulence or it’s otherwise unsafe to walk up and down the aisles, there are exercises you can do in your seat to help keep your blood flowing:

  • Slide your feet back and forth along the floor to help stretch out your thigh muscles.
  • Alternate pushing your heels and toes into the ground. This helps flex the calf muscles.
  • Alternate curling and spreading your toes to improve circulation.

You can also bring a tennis or lacrosse ball on board with you to use to massage your leg muscles. Gently push the ball into your thigh and roll it up and down your leg. Alternatively, you can place the ball under your leg and move your leg over the ball to massage the muscles.

Other things you can do include:

  • Avoid crossing your legs, which can reduce blood circulation.
  • Wear loose, non-constricting clothing.
  • Wear compression stockings if you’re at increased risk for venous thromboembolism (VTE). The stockings stimulate circulation and prevent blood from pooling.

Preventing blood clots during other forms of travel

Whether it’s in the air or on the ground, long periods of time spent in a confined space may increase your risk of blood clots.

  • If you are traveling by car, plan scheduled breaks to stretch your legs or take short walks.
  • If you are on a bus or train, standing, stretching, and walking in the aisles can help. You can also walk in place at your seat if you have enough room, or take a few minutes in the lavatory to stretch your legs or walk in place.

What are the symptoms of a blood clot?

Possible symptoms include:

  • leg pain, cramping, or tenderness
  • swelling in the ankle or leg, usually only on one leg
  • discolored, bluish, or reddish patch on leg
  • skin that feels warmer to the touch than the rest of the leg

It’s possible to have a blood clot and not show any symptoms.

If your doctor suspects you have a DVT, you will be given diagnostic testing to confirm the diagnosis. Tests may include venous ultrasound, venography, or MR angiography.

Symptoms of a pulmonary embolism include:

  • shortness of breath
  • chest pain
  • coughing
  • dizziness
  • irregular heartbeat
  • sweating
  • swelling in the legs

PE symptoms are a medical emergency requiring immediate care. Your doctor may perform a CT scan to confirm the diagnosis prior to treatment.


Long airplane flights may increase the risk for blood clots in some people, including people with additional risk factors, such as personal or family history of blood clots. Preventing blood clots during airplane travel and other forms of travel is possible. Understanding your personal risk, as well as learning preventive steps you can take during traveling, can help.

If you are currently being treated for a blood clot, or have recently completed treatment for one, talk to your doctor before boarding a flight. They may recommend delaying travel or offer medication to help reduce your risk for serious complications.

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