Blood clots, including deep vein thrombosis (DVT) and pulmonary embolism (PE), are serious medical conditions that can lead to life-threatening complications if untreated1 . These clots often develop in people who are immobile for long periods, such as after surgery or during long travel, and can cause sudden blockages in the lungs2 . Understanding your risk factors and adopting preventive measures can significantly reduce the chances of developing blood clots3 .
Blood Clot Risk Factors
Venous thromboembolism (VTE), which includes DVT and PE, is a leading cause of preventable death worldwide4 . The risk factors for blood clots are closely related to Virchow’s triad: venous stasis (slow blood flow), vessel injury, and hypercoagulability (increased tendency to clot) 4. Key risk factors include:
- Older age, especially over 60 years, as the incidence of VTE increases markedly with age4 .
- Male sex, with men having a slightly higher risk than women except during periods of elevated estrogen in females4 .
- Medical conditions such as cancer, heart disease, diabetes, and obesity, which increase clotting risk4 .
- Prolonged immobility, including bed rest, hospitalization, or long travel, which causes venous stasis4 2.
- Smoking, which damages blood vessels and alters platelet function, promoting clot formation4 .
- Recent surgery or trauma, which injures blood vessels and often leads to immobility4 3.
- Hormonal factors in women, including pregnancy, hormonal contraceptives, and hormone replacement therapy, due to elevated estrogen levels4 1.
Additional risk factors include a history of previous blood clots, family history of VTE, varicose veins, and certain inflammatory or infectious conditions3 1. Recognizing these factors is crucial for early prevention and timely intervention.
Blood clots most often occur in people who cannot move well or have had recent surgery or injury. Symptoms such as swelling, redness, and pain in the leg should prompt immediate medical attention to prevent life-threatening complications like pulmonary embolism. 5
Are Blood Clots Hereditary?
Genetics can play a significant role in blood clot risk. Inherited thrombophilias are genetic conditions that increase the tendency to form abnormal clots by disrupting the balance between clotting and anticoagulation4 . Common inherited thrombophilias include:
- Factor V Leiden mutation, the most common inherited clotting disorder, present in about 5% of Caucasians, which increases VTE risk4 .
- Prothrombin G20210A mutation, which raises prothrombin levels and clot risk, found in 1–4% of Europeans4 .
- Deficiencies in natural anticoagulants such as protein C, protein S, and antithrombin, which significantly elevate clot risk4 .
A family history of venous thromboembolism increases an individual's risk of developing blood clots, especially if inherited thrombophilias are present4 . Genetic testing is recommended selectively, based on personal and family history, to guide prevention and treatment strategies6 .
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Ways to Lower Your Risk
Preventing blood clots involves a combination of lifestyle changes, mechanical aids, and sometimes medications. Early mobilization and regular physical activity are key to reducing venous stasis and improving blood flow4 . Below are effective strategies to lower your risk:
Engage in Physical Activity
Physical activity promotes venous return by contracting leg muscles, which helps move blood through the veins and prevents pooling4 7. Even light activities such as walking or leg movements during prolonged sitting are beneficial4 8. After surgery or injury, it is important to start moving as soon as it is safe to do so9 . During long travel, standing up and walking every 1 to 2 hours, flexing and extending knees and ankles, and changing positions frequently can reduce clot risk2 .
Eat a Balanced Diet
A nutritious diet supports vascular health and reduces inflammation, which can lower thrombosis risk4 10. Heart-healthy diets rich in antioxidants and low in saturated fats are recommended to maintain good cardiovascular function4 . Reducing salt intake can also help prevent swelling and improve circulation5 .
Stay Hydrated
Drinking plenty of water (8–10 glasses daily) helps maintain optimal blood flow and prevents dehydration, which can thicken the blood and increase clot risk8 3. Staying hydrated is especially important during periods of limited mobility or travel2 .
Manage Obesity
Obesity increases pressure on leg veins and contributes to poor blood flow, raising the risk of blood clots4 8. Maintaining a healthy weight through diet and exercise reduces this risk and supports overall cardiovascular health4 .
Stop Smoking
Smoking damages the vascular endothelium and alters platelet function, promoting clot formation4 . Quitting smoking is a critical step in reducing the risk of venous thromboembolism and improving overall health4 1.
Reduce Your Stress Levels
While direct evidence linking stress reduction to clot prevention is limited, managing stress supports cardiovascular health and may indirectly lower thrombosis risk4 .
Wear Compression Stockings
Compression stockings apply gentle pressure to the legs, helping prevent blood pooling and clot formation4 9. They are especially useful for people at high risk, such as those recovering from surgery or during long travel7 2.
Take Medications
Most blood clots develop after leaving the hospital, so continue being active at home and follow your doctor’s advice to reduce your risk. 3
In some cases, doctors may prescribe blood-thinning medications (anticoagulants) such as heparin, warfarin, or direct oral anticoagulants (DOACs) to prevent clots5 3. These medications reduce the blood’s ability to clot but require careful monitoring due to bleeding risks5 . Mechanical devices that intermittently compress the legs can also be used in hospital settings3 .
“If you are preparing for surgery or have other risk factors, talk with your healthcare provider about a plan for preventing blood clots. Early movement, compression stockings, and sometimes blood thinners can greatly reduce your risk. 9”
When to Talk to Your Doctor
Having risk factors does not guarantee that a blood clot will form, but it is important to discuss your personal risk with a healthcare provider4 . Your doctor can help assess your risk and recommend appropriate preventive measures, including lifestyle changes and medications4 . Before starting any new exercise or health regimen, consult your provider to ensure safety and effectiveness4 .
Important questions to ask your doctor include:
- What are my specific risk factors for blood clots?
- What symptoms should I watch for?
- What prevention strategies are best for me?
- Do I need medications or mechanical aids like compression stockings?
- How should I manage my risk during travel or after surgery?
Early recognition and treatment of blood clots improve outcomes and reduce complications5 .
Key Prevention Takeaways
- Blood clots can be life-threatening but are often preventable with awareness and action4 .
- Risk factors include age, immobility, medical conditions, smoking, surgery, and hormonal factors4 .
- Regular physical activity, even light movement, is essential to promote blood flow and reduce clot risk4 .
- Wearing compression stockings and staying hydrated support prevention, especially during travel or recovery9 2.
- Consult your healthcare provider to develop a personalized prevention plan, including medications if needed4 .
