Microcapillaries and Endothelium: The ‘Second Heart’

By Dmitry Kaminskiy 

Co-authored with Dr. Arkadi F. Prokopov

In the vast world of longevity research, we often hear about the importance of mitochondria, oxygen, and antioxidants, but there’s another unsung hero that plays a pivotal role in our health and lifespan: the microcapillaries. These tiny blood vessels are critical for transporting oxygen and nutrients throughout our bodies, yet their role is frequently overlooked in the discussions of aging and longevity. In our book Deep Breathing: Maintaining Mitochondrial Quality for Healthy Lifespan Extension, co-authored with Dr. Arkadi F. Prokopov, we devote an entire section to these fascinating structures—often referred to as the body's second heart.

What are Microcapillaries and Why Do They Matter?

Microcapillaries are the smallest blood vessels in our body, only one cell thick, and are responsible for the exchange of oxygen, nutrients, and waste products between blood and tissues. They are found throughout the body but are especially abundant in organs like the heart, brain, and muscles, where efficient nutrient and oxygen delivery is paramount.

What makes microcapillaries so remarkable is not just their role in nutrient transport, but their direct involvement in maintaining the endothelial function—the health of the inner lining of our blood vessels. This endothelial layer plays a crucial role in regulating blood flow, preventing clot formation, and controlling the inflammatory responses in our bodies.

As we age, however, the health of our microcapillaries begins to decline. This decline can lead to poor circulation, diminished nutrient delivery, and an increased risk of cardiovascular disease, cognitive decline, and other age-related conditions. In Deep Breathing, we explore how maintaining and rejuvenating the health of these microcapillaries is a powerful strategy for combating aging and improving overall health.

Microcapillaries as the Body’s Second Heart

One of the most intriguing insights that we explore in the book is the concept of microcapillaries acting as a “second heart.” While the heart is responsible for pumping blood throughout the body, it is the microcapillaries that ensure that every cell receives the oxygen and nutrients it needs to function optimally. Without the healthy function of these microcapillaries, even the healthiest heart can’t compensate for the lack of circulation to the body’s tissues.

Moreover, the endothelial cells lining the capillaries help regulate vascular tone, blood pressure, and the dilation of blood vessels. This complex network ensures that the body adapts to changes in physical activity and environmental stress. In essence, when we think of heart health, we must also consider the health of our microcapillaries and endothelial function.

The Impact of Declining Microcapillary Health

Unfortunately, as we age, microcapillary function naturally deteriorates. This can lead to conditions like vascular stiffness, where the blood vessels lose their ability to expand and contract efficiently. Such stiffness can lead to higher blood pressure, impaired oxygen delivery to tissues, and decreased blood flow to vital organs such as the brain and heart.

For instance, in aging brains, the reduced blood flow through microcapillaries contributes to cognitive decline and conditions like Alzheimer’s disease. In muscles, poor circulation impairs recovery after exercise and diminishes overall physical performance. Similarly, in the skin, reduced capillary function leads to poor wound healing and less radiant skin.

But it’s not all doom and gloom. There’s good news: microcapillary health can be improved with the right interventions. The restoration of microcapillary function is not only possible but necessary for maintaining a healthy lifespan. And this is where the principles we explore in Deep Breathing come into play.

How to Rejuvenate Microcapillaries and Endothelium

In our book, we outline several strategies to restore and maintain microcapillary health, including:

1. Controlled Stress (Hormesis)

Much like how brief periods of exercise or intermittent fasting challenge the body and improve mitochondrial health, controlled stress can stimulate the growth and repair of microcapillaries. This can involve methods such as hypoxic training (brief periods of low oxygen), which forces the body to increase the production of capillaries and improve circulation.

2. High-Intensity Interval Training (HIIT)

Studies have shown that high-intensity interval training (HIIT) can dramatically improve vascular health, including increasing the density of capillaries in muscle tissues. HIIT enhances the body’s ability to transport oxygen and nutrients, which not only improves physical performance but also combats age-related vascular decline.

3. Nutritional Interventions

Certain nutrients can help support endothelial function and promote the health of microcapillaries. For example, omega-3 fatty acids and antioxidants like vitamin C and E are known to improve endothelial function and reduce inflammation. Additionally, compounds like nitric oxide, produced naturally in the body, help relax blood vessels and improve circulation. Consuming foods that boost nitric oxide levels—such as beetroot, dark leafy greens, and citrus fruits—can directly benefit microcapillary function.

4. Breathing Techniques

As explored in previous articles, breathing techniques—such as those that regulate oxygen and carbon dioxide levels—can significantly improve vascular function. For example, deep belly breathing activates the diaphragm and improves the efficiency of the circulatory system. Additionally, controlled breathing in hypoxic conditions (like those used in the Wim Hof Method) encourages the body to adapt to lower oxygen levels and stimulates capillary growth.

5. Angiogenesis Stimulation

Angiogenesis, the growth of new blood vessels, can be stimulated through both physical exercise and specific interventions, such as hypoxia (low oxygen levels) or hyperbaric oxygen therapy (HBOT). HBOT has been shown to promote the growth of new blood vessels and improve circulation, making it a powerful tool in restoring the health of microcapillaries.

The Bottom Line: A Second Heart Worth Nurturing

Maintaining the health of our microcapillaries and the endothelial function is essential to achieving longevity and optimal health. These tiny but vital structures are our body's "second heart," responsible for nourishing every cell. In Deep Breathing, we show you how you can actively rejuvenate and enhance your microcapillary network through strategic, evidence-based practices. By focusing on these often-overlooked aspects of our health, we can unlock new pathways to a longer, healthier, and more vibrant life.

Stay tuned for the next article, where we will dive deeper into the roles of oxygen and carbon dioxide and challenge the prevailing myths about their effects on our health.

Dmitry Kaminskiy Co-author of Deep Breathing: Maintaining Mitochondrial Quality for Healthy Lifespan Extension