2HEART did not conduct these studies.
We cite them because they explore the same problem we are working on:
what happens to the human body during prolonged periods of sitting, and what role the soleus muscle may play in addressing it.
Peer-Reviewed Research on the Soleus Muscle
Primary studies
| Institution | Finding | Year |
|---|---|---|
| University of Houston | 52% reduction in post-meal glucose during soleus activation | 2022 |
| Mayo Clinic | Reduced soleus activity associated with 2x higher health risk | 2021 |
| Sports (Basel) | 32% reduction in prediabetic indicators with soleus activation | 2025 |
Published finding: Sustained soleus activation during seated time produced a 52% reduction in post-meal glucose excursion and a 60% reduction in insulin requirement compared to uninterrupted sitting. Despite making up only ~1% of body mass, the muscle out-consumed every other tissue for glucose during the session.
Hamilton's work established the metabolic case for soleus activation during sitting. It left open the question of what the vascular response to that same activation reveals about an individual's body over time the dimension 2HEART is designed to explore.
Published finding: Approximately 32% reduction in post-meal glucose excursion in prediabetic individuals performing soleus activation during seated time. The effect was present without electromyographic feedback no laboratory equipment required.
This study extends Hamilton's findings to a prediabetic population and removes the laboratory equipment requirement both directly relevant to 2HEART's intended use environment: a seated workday, without clinical supervision.
Published finding: Reduced soleus and calf muscle pump function is an independent risk factor for serious health events in a population-based cohort. People with reduced pump function were twice as likely to experience serious health events over time.
This population-level finding establishes that soleus activity is not only metabolically relevant but also relevant to long-term body health trends. 2HEART is designed to track individual trend over time the same directional logic this study applies at population level.
Published finding: Computational simulation of the soleus pump confirms that during muscle contraction, upward flow increases 4x compared to rest. Valve dysfunction reduces this by approximately 30%. The study provides a mechanical model for how soleus activity drives body movement internally.
This study provides the mechanical foundation for understanding what soleus activation does structurally and why measuring the response it produces is scientifically meaningful.
Published finding: The soleus acts as the primary driver of movement from the lower leg. Published research describes this function as performing the role of a peripheral heart a term reflecting its anatomical and functional role.
The "second heart" concept is not 2HEART's invention. It is a description used in the published scientific literature that reflects a real anatomical function. We use it as a plain-language translation of established physiology.