Surreal illustration of a runner and airplane connected by blood vessels, symbolizing the impact of exercise and travel on blood circulation.

Up in the Air: How Exercise and Air Travel Impact Your Blood Clots

Elliot Brynn in Health & Wellness December 2025 • 4 min read.

"Balancing the benefits and risks for athletes and frequent flyers."

For athletes and frequent flyers, understanding the impact of lifestyle and travel habits on blood health is crucial. Blood clots, while a natural response to injury, can pose serious risks when they form inappropriately. Known as venous thromboembolism (VTE), this condition can manifest as a deep vein thrombosis (DVT), typically in the legs, or as a pulmonary embolism (PE) in the lungs. Awareness and preventive strategies are key, especially for those who combine intense physical activity with air travel.

Exercise and air travel, seemingly disparate activities, both influence the body's hemostatic balance—the ability to control blood loss. Exercise stimulates both coagulation and fibrinolysis, the processes of clot formation and breakdown, respectively. Air travel, particularly long-haul flights, is an established risk factor for thrombosis due to prolonged immobility, hypoxia, and dehydration. But what happens when these two factors combine?

This article explores the complex interplay between exercise, air travel, and blood clot formation. It will delve into how each activity independently affects the body's coagulation and fibrinolytic pathways, examine potential confounding variables, and offer practical strategies to mitigate risks, ensuring safer skies and healthier travels.

The Exerciser's Edge: Benefits and Potential Risks

Surreal illustration of a runner and airplane connected by blood vessels, symbolizing the impact of exercise and travel on blood circulation.

Regular physical activity is often touted for its cardiovascular benefits, including a reduced risk of thrombotic events. However, intense, acute physical exertion can paradoxically increase the risk of blood clot formation. This is particularly true during endurance events like marathons and triathlons, or during extensive resistance training, where the body's coagulation system is highly activated.

Here's a breakdown of the key effects of exercise on hemostasis:

Coagulation Activation: Strenuous exercise triggers a hypercoagulable state, decreasing the activated partial thromboplastin time (aPTT) and increasing levels of coagulation factors like Factor VIII and von Willebrand factor (VWF).
Thrombin Generation: Markers of thrombin formation, such as thrombin-antithrombin complexes (TAT) and prothrombin fragments 1 + 2 (PTF 1 + 2), rise post-exercise, indicating increased clot formation.
Fibrinogen Response: While fibrinogen, a key protein in clot formation, may increase, decrease, or remain unchanged after exercise, its role in promoting platelet aggregation and blood viscosity remains significant.
Fibrinolysis Activation: Acute exercise initiates fibrinolysis, with the release of tissue plasminogen activator (tPA) to break down clots. However, the balance between coagulation and fibrinolysis can be disrupted, especially in ultra-endurance events where coagulation activity remains elevated even as fibrinolysis returns to normal.

Vigilance is crucial for individuals who exercise intensely, especially athletes traveling for competition. The risk of VTE can persist for up to a month after the event and travel. The combined effects of air travel and intense exercise may disrupt the coagulation-fibrinolytic balance, increasing the risk of VTE.

Stay Safe in the Skies and on the Ground

Both intense exercise and air travel independently pose a risk for developing VTE, and this risk compounds when combined. While athletes and frequent travelers shouldn't shy away from physical activity or travel, awareness and proactive measures are key.

Here are some strategies to consider:

While the science continues to evolve, being informed and proactive is your best defense against travel-related blood clots. Stay active, stay hydrated, and consult with your healthcare provider to tailor a prevention plan that suits your individual risk profile and lifestyle.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1055/s-0038-1670640, Alternate LINK

Title: Exercise And Air-Travel–Induced Alterations In Blood Hemostasis

Subject: Cardiology and Cardiovascular Medicine

Journal: Seminars in Thrombosis and Hemostasis

Publisher: Georg Thieme Verlag KG

Authors: Brian Kupchak

Published: 2018-10-03

Everything You Need To Know

What is venous thromboembolism (VTE), and why should athletes and frequent flyers be aware of it?

Venous thromboembolism, or VTE, is a condition where blood clots form inappropriately, often manifesting as deep vein thrombosis (DVT) in the legs or a pulmonary embolism (PE) in the lungs. These clots can impede blood flow and pose serious health risks, especially for those with predisposing factors or those undergoing situations that increase coagulation.

How does strenuous exercise impact blood clot formation, specifically concerning coagulation factors and fibrinolysis?

During intense physical activity, the body's hemostatic balance is significantly affected. Exercise stimulates coagulation by decreasing the activated partial thromboplastin time (aPTT) and increasing levels of coagulation factors like Factor VIII and von Willebrand factor (VWF). It also raises markers of thrombin formation, like thrombin-antithrombin complexes (TAT) and prothrombin fragments 1 + 2 (PTF 1 + 2). While exercise also activates fibrinolysis through the release of tissue plasminogen activator (tPA), the coagulation activity may remain elevated, particularly in ultra-endurance events.

Why does air travel increase the risk of blood clots, and what physiological factors contribute to this risk?

Air travel, especially long-haul flights, increases the risk of thrombosis due to factors such as prolonged immobility, hypoxia, and dehydration. These conditions can disrupt the body's normal coagulation-fibrinolytic balance, leading to an increased risk of developing VTE. The reduced air pressure and constrained seating can further exacerbate the risks associated with immobility.

Does combining intense exercise with air travel significantly increase the risk of developing a blood clot (VTE)?

Yes, intense exercise and air travel independently pose risks for VTE, and these risks can compound when combined. For instance, an athlete traveling for a competition might experience increased coagulation from the physical exertion and further risk from the prolonged immobility during air travel. This combination can disrupt the coagulation-fibrinolytic balance, increasing the overall risk of VTE. The risk of VTE can persist for up to a month after the event and travel.

What specific details about preventing blood clots are not covered, and what additional factors might be relevant for a comprehensive understanding of VTE risk management in athletes and frequent flyers?

While the text discusses the effects of exercise on coagulation and fibrinolysis, influencing factors such as Factor VIII, von Willebrand factor (VWF), tissue plasminogen activator (tPA), thrombin-antithrombin complexes (TAT) and prothrombin fragments 1 + 2 (PTF 1 + 2) there isn't a deep dive into specific preventative measures or personalized risk assessment. Future research and resources could explore tailored strategies for different individuals, considering factors such as age, genetics, and pre-existing conditions, to provide more precise guidance for minimizing VTE risks associated with exercise and air travel.