Lower Risks from Prolonged Sitting

Most of us sit far more than we realize, whether at work, commuting, eating, relaxing, or during long flights.

A recent observational study of nearly 90,000 people found that sitting more than 10.5 hours a day was associated with a 62% increase in risk of cardiovascular death.¹

About a quarter of the people in the study sat that much.

A major risk stemming from prolonged sitting is deep vein thrombosis, blood clots that most often develop in the legs.^2,3 These clots can be life-threatening if they break loose and travel to the lungs.^4,5

Two plant-based ingredients, nattokinase,^6-9 and French maritime pine bark extract,^10-12 have been shown to promote healthy blood flow and help prevent deep vein thrombosis.

In a randomized-controlled trial, a nattokinase-pine bark blend was shown to lower the risk of developing blood clots (deep vein thrombosis) when used in combination with an exercise program, in people on seven to eight hour-long airplane flights.¹³

Dangers of Deep Vein Clots

After heart attacks and strokes, the third leading cause of cardiovascular death is pulmonary embolism.¹⁴

This potentially fatal condition can occur when a clot from deep vein thrombosis (DVT) travels to the lungs, blocking blood flow.^15,16

Thrombosis is the formation of a blood clot within a blood vessel, potentially obstructing blood flow. These clots can form in veins or arteries and can lead to serious complications if they break loose and travel to other parts of the body. 

Common signs of deep vein thrombosis may include pain and swelling in the affected leg. However, sometimes there are no warning signs, putting people at even greater risk of pulmonary embolism.¹⁵

Post-thrombotic syndrome arises due to pressure, inflammation, and incomplete vein healing after a clot. This can cause valve damage, vein blockage, and worsening venous insufficiency. The symptoms of this condition are typically chronic pain and swelling in the legs, and even venous ulceration.^4,17

Many people are unaware that they are at risk of these conditions.¹⁶

Risk Factors

A sedentary lifestyle, and even sitting for a long period, dramatically increases the risk of deep vein thrombosis. Lack of movement reduces blood flow, which can result in a clot.^16,18

That explains why deep vein thrombosis is of particular concern on long airplane flights.^19,20 Prolonged air travel significantly increases the risk of deep vein thrombosis, with the elevated risk lasting for more than four weeks after long flights.²⁰

Deep vein clots can happen at any age, but the risk doubles every 10 years after age 40.²¹

Several other factors increase the risk of deep vein thrombosis, including bed rest after surgery or injury,²⁰ obesity, diabetes, cardiovascular diseases, high blood pressure, infections, smoking, and tall height.²²

Fortunately, scientists have found that an enzyme called nattokinase and an extract of French maritime pine bark can help prevent deep vein thrombosis.

How Nattokinase Helps

Traditional Japanese diets include a fermented soybean food called natto, which is associated with health and longevity.²³

Natto and its extracts are rich in the enzyme nattokinase, which has been shown to:^8,9,24,25

• Suppress the development of unwanted blood clots, and
• Break down existing clots.

A systematic review and meta-analysis of human randomized controlled trials found that nattokinase can also help reduce blood pressure.²⁶ High blood pressure is linked with an increased risk of deep vein thrombosis.^21,27

Human Trials of Nattokinase

The anticlotting actions of nattokinase were demonstrated in a placebo-controlled study in which 12 healthy men took a single dose of 2,000 fibrinolytic units of the enzyme.⁹

Within just two hours, the nattokinase:⁹

• Increased antithrombin, which inactivates several clotting enzymes,
• Decreased a pro-clotting protein called factor VIII, and
• Increased fibrinolysis, a process that helps prevent blood clots from growing.

What You Need To Know

Defend Against Deep Vein Thrombosis

• Sitting too long increases the risk of deep vein thrombosis in the legs. These clots can travel to the lungs, causing potentially fatal pulmonary embolism.
• The enzyme nattokinase, found in fermented soybeans, has been shown to help prevent clotting in multiple ways.
• French maritime pine bark extract also helps prevent deep vein clotting and reduces leg swelling.
• In a clinical study, a combination of these ingredients reduced leg swelling and completely prevented deep vein thrombosis in high-risk passengers on long flights.

Anticlotting activity continued through the eight-hour monitoring period.⁹

Nattokinase may also help those who have already sought treatment for deep vein thrombosis with an anticoagulant (blood-thinning) drug or vascular surgery.

In a clinical trial of 153 adults with vascular diseases (including deep vein thrombosis and venous insufficiency) participants were divided into the following three groups:

Each group received 2,000 fibrinolytic units of nattokinase daily along with conventional treatment for a month.⁸

During the follow-up period, patients were also tested for coagulation markers.

The results demonstrated that nattokinase alleviated clinical symptoms without adverse reactions or interactions in all three groups. No new incidences of vascular disease were observed during the follow-up period.⁸

Pine Bark Provides Protection

French maritime pine bark extract comes from trees on the coast of southwest France.²⁸

The extract is rich in beneficial compounds, including procyanidins.^29,30

Pine bark extract standardized to 65% procyanidins²⁹ has been shown to support cardiovascular health and reduce deep vein thrombosis risk by:^28,29

• Inhibiting platelets from clumping to form clots,
• Decreasing inflammatory processes,
• Increasing antioxidant levels, and
• Promoting elasticity of blood vessels to support blood flow and reduce risk of clot formation.²⁹

Pine Bark Benefits

Multiple human studies have demonstrated that French maritime pine bark extract may help inhibit lower leg swelling during extended air travel, with effectiveness equal to or better than compression socks.^12,31,32 One study demonstrated its ability to prevent deep vein clots, including in those at high risk.¹⁰

Approximately one-third of individuals diagnosed with these deep vein clots, known medically as deep vein thrombosis (DVT), experience a recurrence within 10 years.³³

In addition, up to 50% of those with deep vein thrombosis suffer from post-thrombotic syndrome (PTS) as a long-term consequence.^34,35

In a longitudinal study involving 815 participants, bi-annual assessments were conducted over six years following an initial deep vein thrombosis episode. All participants followed standard management, including the use of compression stockings, weight control, and regular physical activity. Some also received adjunct therapies—aspirin, prescription anticoagulants, or 200 mg of French maritime pine bark extract daily.¹²

Recurrence rates for post-thrombotic syndrome incidence varied by intervention:

• 14.9% with standard treatment alone,
• 12.9% with the addition of aspirin,
• 6.7%–10.7% with anticoagulant drugs, and
• 3.6% with French maritime pine bark extract.

The pine bark extract demonstrated the greatest efficacy in reducing long-term thrombotic complications.

A Preventive Combination

Impressed by the anticlotting properties of nattokinase and French maritime pine bark, scientists created a combination of the two ingredients.

They tested this combination in 204 people at high risk of deep vein thrombosis who were flying between New York and London, a seven-to-eight-hour flight.¹³

Passengers took the blend or a placebo two hours before flying and again during the flight (six hours after the first dose). All subjects were advised to stand and move their legs occasionally while flying.

No travelers taking the nattokinase-pine bark blend developed deep vein thrombosis, while 5.4% of the placebo group did.

In addition, the treatment group had a 15% decrease in lower leg swelling (edema), while the placebo group had a 12% increase.

These findings suggest that a combination of nattokinase and French maritime pine bark extract may help prevent dangerous deep vein thrombosis.

Summary

Extended sitting increases the risk of deep vein thrombosis and pulmonary embolism, a leading cause of cardiovascular death.

Nattokinase and French maritime pine bark extract help prevent deep vein clot formation, resolve unwanted clots, and support vascular health.

A combination of these ingredients has been clinically shown to prevent deep vein thrombosis and inhibit lower leg swelling during long flights.

If you have any questions on the scientific content of this article, please call a Life Extension Wellness Specialist at 1-866-864-3027.

References

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2. Yao J, Han M, Shi J, et al. Prognosis and Factors 4 to 10 Years After Deep Vein Thrombosis: A Long-Term Follow-up Cohort Study. Clin Appl Thromb Hemost. 2024 Jan-Dec;30:10760296241266820.
3. Chang HC, Burbridge H, Wong C. Extensive deep vein thrombosis following prolonged gaming (‘gamer’s thrombosis’): a case report. J Med Case Rep. 2013 Oct 8;7(1):235.
4. Frank C, Ratchford EV, Moll S. Vascular Disease Patient Information Page: A guide for patients with newly diagnosed deep vein thrombosis or pulmonary embolism. Vasc Med. 2023 Oct;28(5):481-6.
5. Pagano T, Fabbri IS, Benedetto M, et al. Predicting in-hospital mortality in patients admitted from the emergency department for pulmonary embolism: Incidence and prognostic value of deep vein thrombosis. A retrospective study. Clin Respir J. 2024 Jan;18(1):e13697.
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8. Gallelli G, Di Mizio G, Palleria C, et al. Data Recorded in Real Life Support the Safety of Nattokinase in Patients with Vascular Diseases. Nutrients. 2021 Jun 13;13(6).
9. Kurosawa Y, Nirengi S, Homma T, et al. A single-dose of oral nattokinase potentiates thrombolysis and anti-coagulation profiles. Sci Rep. 2015 Jun 25;5:11601.
10. Belcaro G, Cesarone MR, Rohdewald P, et al. Prevention of venous thrombosis and thrombophlebitis in long-haul flights with pycnogenol. Clin Appl Thromb Hemost. 2004 Oct;10(4):373-7.
11. Rohdewald P. Pleiotropic Effects of French Maritime Pine Bark Extract to Promote Healthy Aging. Rejuvenation Res. 2019 Jun;22(3):210-7.
12. Belcaro G, Cornelli U, Dugall M, et al. Long-haul flights, edema, and thrombotic events: prevention with stockings and Pycnogenol(R) supplementation (LONFLIT Registry Study). Minerva Cardioangiol. 2018 Apr;66(2):152-9.
13. Cesarone MR, Belcaro G, Nicolaides AN, et al. Prevention of venous thrombosis in long-haul flights with Flite Tabs: the LONFLIT-FLITE randomized, controlled trial. Angiology. 2003 Sep-Oct;54(5):531-9.
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17. Tsiamita O, White K. Post-thrombotic syndrome and chronic thromboembolic pulmonary hypertension: diagnosis and management. Br J Hosp Med (Lond). 2023 Aug 2;84(8):1-10.
18. Harrington LB, Cushing-Haugen KL, Nguyen S, et al. Sedentary behaviors and venous thromboembolism risk among older women: the Objective Physical Activity and Cardiovascular Health study. J Thromb Haemost. 2025 Feb 20.
19. McKerrow Johnson I, Shatzel J, Olson S, et al. Travel-Associated Venous Thromboembolism. Wilderness Environ Med. 2022 Jun;33(2):169-78.
20. Available at: https://www.cdc.gov/yellow-book/hcp/travel-air-sea/deep-vein-thrombosis-and-pulmonary-embolism.html. Accessed April 25, 2025.