How the heartbeat influences our perception of the outside world

Since we are little we learn there are two essential organs for life: the brain and the heart. Both represent that duality that shapes human existence. While one is engaged in emit and receive signals from the rest of the organs (including the heart), As well as generating perceptions of what surrounds us through the senses, the other keeps the body afloat, pumps blood to the rest of the body, nourishing the cells. And all in every beat.

Thus, the brain is viewed from the biological point of view as the center of who we are and what we do. It is the one that governs our senses, sets our movements in motion and preserves the most essential attribute for survival: memory. The heart, on the other hand, is relegated to the function of supporting all the machinery that is our organism. In recent years, a series of academic studies have been published that have given scientists new ideas about the role that the heart plays in our way of perceiving and interacting with the environment and that has often been overlooked, entirely attributed to them to the brain.

During systole, when the heart pushes blood through the blood vessels, the body is much more sensitive

Already in the late nineteenth century, psychologist William James and doctor Carl Lange They hypothesized that the emotional states we go through are the brain's perception of certain bodily changes that respond to a stimulus such as a heart that beats very fast or rapid, deep breathing. These are undoubtedly physiological expressions of certain emotions like fear or anger. Since then, scientists have found many examples of this physiological arousal that later lead to emotional arousal, as if the mood of fear was not the reason the heart is racing, but the other way around.

We know that cardiac activity is divided into systole (when the muscle contracts and pumps blood) and diastole (when it relaxes and receives it). Starting in the 1930s, scientists began to discover that systole dampens the sensation of pain and slows down reflexes that show shock. In addition, pressure sensors send signals about cardiac activity to brain regions that inhibit it. "This is very useful", values Ofer Perl, a researcher at the Inahn School of Medicine at Mount Sinai Hospital in New York, in a 'Quanta Magazine' article that reviews all of these theories. "The brain must constantly balance and integrate internal and external signals, so it cannot pay attention to everything at once." Hence, the heart also contributes less to perceiving the environment

"I really think of sense perception as a kind of swing"he assures Sarah Garfinkel, neuroscientist at the Brighton and Sussex Medical School in England. "When something internal is detected, this sense is muffled by the processing of external signals. When a heartbeat happens, it's just causing the weight to drop to one side of that rocker."

The heart beats faster in a situation of fear because "it does not want to be sensitive to pain, but to escape the threat"

A study published in the journal 'Proceeding of the National Academy of Sciences' brought together a group of participants who were administered a barely detectable electric shock with the sense of touch to ensure that the sensation was not registered by the brain. At the end of the experiment, those people were more likely to perceive this tiny electrical stimulus during diastole, whereas in systole it was not. What does this mean? During systole, when the heart pushes blood through the blood vessels, the body is much more sensitive, hence the pulse can be felt. The brain, on the other hand, suppresses or does not pay attention to these types of minimal physical signals, since they do not get to provide enough information about the environment.

And fear?

In 2014, Garfinkel and his team demonstrated that the way we process fear and other threatening stimuli is not inhibited in systole. Although this heart movement activates the inhibitory regions of the brain, it also activates the amygdala, the specific area in charge of responding to fear. The scientists envisioned the participants a series of faces between menacing and peaceful. Not surprisingly, people reacted more intensely by looking at those that involved threat. "The most surprising thing about fear is that it breaks through"Garfinkel asserts. "It is impervious to this inhibitory effect on the heart. "

Hence, when we feel terror or a threat, whether real or fictitious, the heart beats faster and stronger. "He is in a state of fear, he does not want to be sensitive to pain," stresses the scientist. "You want to escape the threat, but also stay alert. Fear after all is a feeling that can help you survive. "

But not only in the face of fear. The heart maintains close communication with its environment and regulates the inner world. Another article published in the magazine 'Cognition' revealed that blinks occur more frequently in systole, while in diastole we tend to keep our eyes fixed. The body seems to time the exposure time of our sight to the environment so that there is a balance between the internal and external world. "Systole is the point where you are least sensitive to the world, when brain processing tends to slow down and the inner world rules," Garfinkel summarizes.