What is Deep Vein Thrombosis (DVT)?

Mayfair • Feb 26, 2018

With the popularity of long-distance air travel, there has been much discussion about sitting for long periods of time, the risk of Deep Vein Thrombosis (DVT), and what causes it.

A blood clot (thrombus) can form in superficial veins or deep veins. In superficial veins they rarely cause problems, but in deep veins they can break loose and travel through the bloodstream, possibly blocking blood flow.

DVT most often occurs in the legs and can cause pain or swelling. If a blood clot travels through the bloodstream and lodges in the lungs, it can cause a pulmonary embolism.

DVT can have long-lasting problems, such as damage to your leg vein. Not to mention, a pulmonary embolism can be life-threatening.

What are the symptoms of DVT?

Sometimes DVT can occur without noticeable symptoms, but the more common ones are:

  • Swelling.
  • Pain that starts in your calf and feels like cramping or soreness.
  • A feeling of warmth.

What are the risk factors for DVT?

Blood clots from DVT can be caused by anything that prevents your blood from circulating normally. Risk factors include: 

  • Heredity – inheriting a blood-clotting disorder or a family history of DVT or pulmonary embolism.
  • Limited movement – due to a long hospital stay, paralysis, or sitting still for long periods of time increases the risk of blood clots because your calf muscles don’t contract to help circulate blood.
  • Injury or surgery – can increase your risk of blood clots.
  • Pregnancy or being overweight – increases pressure in the veins in your pelvis and legs which raises your risk.
  • Medications – some medications can increase your blood’s ability to clot, such as certain cancer treatments, birth control pills, or hormone replacement therapy.
  • Smoking – affects blood clotting and circulation.
  • Inflammatory bowel disease – such as Crohn's disease or ulcerative colitis, increase your risk.
  • Age – being older than 60.

The more risk factors you have, the greater your risk of DVT, but simple lifestyle changes can lower your risk. Regular exercise, losing weight, eating healthy, and quitting smoking are a great start. As well, avoid remaining in one position. Stand or walk occasionally if you sit for long periods and try to get moving as soon as possible after bed rest or surgery.

If you suspect you have DVT, speak to your health care practitioner. They may request you have a Vascular Ultrasound to assess blood flow through your veins and check for blood clots.


Centers for Disease Control and Prevention (2018) Venous Thromboembolism (Blood Clots). www.cdc.gov. Accessed February 15, 2018.

Healthwise Staff (2017) Deep Vein Thrombosis. www.myhealth.alberta.ca. Accessed February 15, 2018.

Mayo Clinic Staff (2017) Deep vein thrombosis (DVT). www.mayoclinic.org. Accessed February 13, 2018.

Symptoms, Disease Prevention