How the heart and brain literally shape one another

As we traverse the highs and lows of life, we are continually witness to how our hearts respond and are shaped in unexpected ways as our rich inner lives unfold and evolve. Yet it turns out that this truth is more than just metaphorical. Amazingly, scientific studies are beginning to show just how intimately the brain, heart, and body are connected—so much so that the very physical structure of the heart can change in response to emotional events in our life, and the activity of the heart in turn can mould the brain to affect how we think, feel, and make decisions.

At times of heartbreak, our emotional world can become warped by the sheer pain of our loss. Startlingly, in cases of “takotsubo cardiomyopathy”, this warping is not just emotional, but physical. In a fascinating TED talk, the cardiologist Dr Sandeep Jauhar explains how “the emotional heart intersects with its biological counterpart in surprising and mysterious ways”. Takotsubo cardiomyopathy was first described by doctors in Japan, who noted the bizarre shape sometimes taken by the hearts of patients suffering from extreme emotional stress. They named the condition after the takotsubo, a pot with a wide base and narrow neck, which resembles the warped physical shape of the sufferer’s heart.

For the sufferers of takotsubo cardiomyopathy, this change in the shape of their heart is more than just a bizarre curiosity. The reshaping of the heart reduces its capacity to pump blood around the body, endangering the functioning of the organs and risking severe illness or death. Dr Jauhar explains that stress itself is one of the main predictors of heart disease, more so even than exercise or diet. Far from being a “machine”, our physical hearts are intimately connected and sensitive to our emotional lives.

Just as the physical heart can respond to the way we think and feel, scientific studies have shown how our thoughts and emotions are sensitive to the activity of our heart. The heart contains its own “mini-brain” of 40,000 brain cells, which receive and send messages to the brain, allowing the heart and brain to work together to regulate our heartbeat and arousal level via the autonomic nervous system. Many of these signals fluctuate with the natural pulse of the cardiac cycle, which is composed of the heartbeat itself (occurring during the “systole” phase) separated from the next heartbeat by a short pause (known as the “diastole” phase).

Neuroscientists investigating the effects of the heart on our behaviour and brain activity have made several surprising discoveries. Scientific experiments have shown that depending on whether a person’s heart is at systole (on the heartbeat) or diastole (off the heartbeat), key aspects of our moment-to-moment intelligence and judgement can be affected. For example, during systole, memory has been found to worsen, the pain felt from an electric shock decreases, and fearful faces evoke more intense emotional reactions.

This elevated fear response accompanying the heartbeat correlates with increased activation of the amygdala, a key brain region controlling the “fight-or-flight” response, which has a direct effect on decision-making regions, such as the prefrontal cortex. The conclusion is: our heart can literally influence the way we think and feel on a moment-by-moment basis.

Interestingly, the scientific evidence available so far also suggests that individuals with a greater inner awareness (interoception) about what is going on in their body, including their heart, are better able to maintain their capacity to remember, learn, and make decisions across the cardiac cycle. Within the brain, the insula is the key region responsible for interoception.

Mindfulness practices, such as those taught by the Heart-Based Living Initiative, emphasise moment-to-moment awareness of the body and have scientifically measurable effects on the insula. Mindfulness has been shown to enhance the strength of neural connections between the insula and decision-making regions of the brain in the prefrontal cortex. Mindfulness also stimulates neuroplasticity in the insula, potentially allowing it to “rewire” itself in ways that enable interoception to be developed and strengthened with practice. With mindful awareness, we can learn to better integrate the messages from our heart and body, and improve the inner balance within our autonomic nervous system.

Science and mindfulness practice are both helping us to understand the intimate ways in which the heart, brain, and body are connected. As we begin to appreciate just how sensitive the physical structures of our body are to the things we normally label as “mental”, and how sensitive our mind is to the physical activities of our body, we might be inspired to approach our wellbeing through a new lens. Caring for our emotional heart, we care for our physical heart. Caring for our physical heart, we care for our emotional heart. Our heart, body, and brain hold mysteries—and mindfulness, care, and curiosity (plus a healthy dollop of science!) could be just the keys to unlock their treasures. 

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Doran Amos

Doran has been practising mindfulness since 2006. He is passionate about using heart-based practices to help himself and others fall in love with humanity’s potential and with the Earth again. He is a writer, neuroscientist, and sometime funky dancer.