About This Research
This study was conducted by researchers affiliated with Mayo Clinic and published in Blood, a peer-reviewed medical journal of the American Society of Hematology. The research followed more than 1,500 participants and examined whether reduced calf muscle pump function was associated with future venous thromboembolism (VTE) risk and mortality.
The calf muscle pump — driven primarily by the soleus muscle — plays a critical role in moving blood from the lower legs back toward the heart.
This population-level study from Mayo Clinic demonstrates that reduced calf pump function is not just a theoretical concern. It is associated with measurable differences in long-term health outcomes.
For people who spend extended hours seated, this research raises an important question: Does reduced soleus activity during prolonged sitting affect calf pump function over time?
The Houghton study (2021), conducted at Mayo Clinic and published in Blood Journal, investigated whether reduced calf muscle pump function is an independent risk factor for serious health events.
The key finding: people with reduced calf pump function were approximately twice as likely to experience serious health events over the follow-up period compared to those with normal pump function. This association remained significant even after adjusting for other risk factors.
The study focused on venous thromboembolism (VTE), a condition involving blood clots in the veins, but the findings have broader implications for understanding the role of the calf pump in circulatory health.
The calf muscle pump helps move blood from the lower legs back toward the heart.
When calf pump activity is reduced, blood can remain in the lower limbs for longer periods.
Researchers have long studied whether impaired calf pump function contributes to vascular and circulatory problems.
The Houghton study was designed to investigate this relationship in a large population.
This was a population-based cohort study conducted in Olmsted County, Minnesota. Researchers measured calf muscle pump function in participants using established techniques and followed them over time to track health outcomes.
The study design allowed researchers to examine whether reduced calf pump function predicted future health events, independent of other known risk factors such as age, body mass index, and medical history.
The calf muscle pump is the mechanism by which calf muscles — primarily the soleus — compress deep veins in the leg, pushing blood upward toward the heart. One-way venous valves prevent blood from flowing backward.
This pump is essential for maintaining circulation, especially when standing or walking. During prolonged sitting, calf muscle pump activity decreases substantially, which may affect venous return from the lower legs.
View glossary definition: Calf pump function →
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The Houghton study establishes that calf pump function is not just a physiological detail — it is associated with meaningful differences in long-term health outcomes.
2HEART is being developed to support soleus activity during seated hours, when the calf pump naturally slows. The device is intended to support calf pump engagement during prolonged sitting.
2HEART did not conduct this study. We cite it because it explores the same problem we are working on: what happens to the human body during prolonged sitting, and what role the soleus muscle may play in addressing it.
Read the original study on PMC →
Research summary disclaimer. This page summarizes independent peer-reviewed research. 2HEART did not conduct this study. The summary is provided for educational purposes. The findings do not constitute validation of 2HEART or its intended outcomes.