Heart-Brain Axis

Emotions and the Heart-Brain Axis

Jessica Reader Blog

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Your beloved family member passes away. You hold your newborn baby for the first time. You hear news of a tragic accident. You say yes to marriage. Life is marked by emotional moments. These are moments that make you feel on a deep level—and nowhere more intensely than in the heart. 

Few people would deny that we feel emotions in our heart. We receive information through the brain and then have sensations in our heart. But what many people don’t realize is that the communication between the heart and the brain goes both ways. 

The study of the communication networks between the heart and the brain has emerged as a new field, called neurocardiology. Just like we have a gut-brain axis of communication, we also have a heart-brain axis. 

Like all networks and relationships in the human body, the heart-brain axis is extremely complex. It’s also fascinating. Read on to get the undeniable evidence of a link between your emotions and your heart as well as the physiology to explain the link between your heart and your brain. Stick with me until the end of the article, and you’ll learn some practical ways to harness the power of the heart-brain axis. 

3 Proven Ways that Emotions are Linked to the Heart

Before we dive into the physiology of the heart-brain axis, let’s first look at the relationship between emotions and the physical health of the heart. Do emotions affect heart health? Does heart health affect emotions? The road might go both ways. 

1. Stress and Heart Disease

Mental and emotional stress is not good for the heart. The INTERHEART Study, which involved thousands of participants from 52 different countries found that stresses from home, work, finances, or life events dramatically increased the risk of heart attack. 

A study just recently published in the British Medical Journal of more than 100,000 men and women in Sweden found that stress-related disorders (like post-traumatic stress disorder or other stress reactions) increased the risk of heart disease by 64%. 

On the flip side, reducing stress may offer benefits for cardiovascular health. One study found that people who had more social support experienced faster and more extensive recovery after a stroke. 

2. Depression and Heart Disease

Depression is strongly linked with heart disease. People who have depression are more likely to develop cardiovascular disease and also to die from cardiovascular disease than the general public. Also, the more severe the depression is, the worse the risk. 

A study that was published in 2019 evaluated more than 32,000 US adults who had depression or anxiety. People who struggled with persistent symptoms of these mood problems experienced double the risk of coronary artery disease. The study also found that improvements in mood were associated with a lower coronary artery risk. 

3. “Broken Heart Syndrome”

One of the most undeniable pieces of evidence to support a link between emotions and the heart is a condition called Takotsuba syndrome. Takotsuba is the name for a Japanese octopus trap, which is shaped like a pot with a narrow neck. The condition is named after this trap because the heart takes on its characteristic shape. 

Takotsuba syndrome develops in response to intense emotions, such as shock or grief. It is a physical condition, with symptoms that resemble a heart attack, that has a direct emotional cause. Exactly why this “broken heart syndrome” occurs is not well understood, but a chemical cascade related to the stress response is likely involved. 

3 Proven Ways that the Heart is Linked to the Brain

It’s clear that emotions are linked with the physical health of the heart. But how, exactly does this relate to the brain? What is going on with the physiology of the body? Let’s look at three of the ways scientists have found that the heart is linked to the brain. 

1. The Amygdala 

Deep in the center of the brain is a tiny, almond-shaped bundle of nerves, called the amygdala. As part of the limbic system, the amygdala is considered the emotional center of the brain. It is linked to the experiences of both fear and pleasure. The amygdala also stores memories of emotional events. That feeling you had when you first held your newborn baby? The amygdala remembers.  

Studies in adults as well as teens show that emotions like fear, anger, or happiness trigger activation of the amygdala that correlate with changes in heart rate. But which comes first? It’s possible that the communication goes both ways. Some intriguing evidence suggests that a more consistent and harmonious heart rate (i.e., higher heart rate variability) may support healthier emotional regulation via interactions with the amygdala. 

2. The Vagus Nerve and the Intrinsic Nervous System of the Heart

We know that the autonomic nervous system (including the sympathetic and parasympathetic) regulates heart rate and blood pressure. One of the major nerves communicating from the brain to the heart and other internal organs is the vagus nerve (cranial nerve X). But 80% of vagal nerve fibers extend NOT from the brain to the internal organs but actually in the opposite direction. 

What’s more is that the heart has its own intrinsic nervous system. This network of some 40,000 nerve cells, which resemble the nerve cells in the brain, have been called by some the “heart brain.” This intrinsic system of nerves connects with the sensory fibers of the vagus nerve to communicate with the top-most brain in your head. When we start to see phenomena like we discussed above—where heart rate variability influences the amygdala—it’s likely that the vagus nerve is at play. 

3. The Hormonal Cascade 

Hormones are produced by the endocrine system, but there is a close relationship between the endocrine and nervous systems. For example, mental stress triggers the release of cortisol, and sex hormones influence cognitive function. Now we are discovering that the heart also interacts with this neuro-endocrine system. 

Some of the muscle cells of the heart have been found to resemble endocrine cells and release hormones. One of the hormones released by the heart is oxytocin—a hormone that has historically been associated with feelings of love and intimacy. We don’t know much about whether hormones play a role in the heart-brain axis, but it opens up an intriguing world of possibilities.  

Harnessing the Power of the Heart-Brain Axis

Once you are aware of the heart-brain axis, you have the power to harness it to improve your health and happiness. One of the simplest take-aways is that being proactive about your mental and emotional health will likely also support the health of your heart and brain. 

When you do things that bring you joy, you are not just having fun but actually improving your health. Activities that used to feel like self-indulgence (like taking a bubble bath, ditching work to see a movie, or having a moms’ night out to laugh with your friends) are now acts of self-care. 

In addition to tending to your emotional health, there are targeted strategies that tap into the power of the heart-brain axis. Multiple brain integration is a strategy that is taught by Grant Soosalu and Marvin Oka that teaches you to align your three brains (brain, gut, and heart) for greater happiness. HeartMath is a biofeedback tool that helps you regulate your heart-rate variability for better mental and emotional health.   

Knowledge of the intricate communication network between the heart and the brain opens worlds of possibilities. Now you can live from the heart and enjoy better health.

About the Author

Sarah Cook, ND, is an instructor at the Nutrition Therapy Institute. She is also the owner of ND Pen, providing branding, copywriting, and website design services for integrative healthcare practitioners. Connect with Sarah at www.ndpen.com. 

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