Thinking can affect your heart rate. For example, in healthy people, it can change not only with physical activity, but even with the thought of it. The rhythm is known to slow down with meditation and speed up in anxiety and surprise. However, how conscious or unconscious perception (for example, listening to stories) affects the pulse is poorly understood.
Previously, some studies have shown that physiological indicators in humans – including heart rate – are sometimes synchronized. This can happen when experiencing a shared experience or simply when staying in the same location. But what exactly factors influence this is practically unknown. Scientists from the USA and France have tested what exactly contributes to the synchronization of the heart rhythm when listening to texts.
Scientists conducted four experiments. First, 27 volunteers listened to excerpts from Jules Verne’s book Twenty Thousand Leagues Under the Sea. During this time, each of the study participants underwent electrocardiography. The changes she recorded depended on the events in the book. For most, the heart would speed up and slow down in the same episodes of the story. Significant rhythm synchronization was observed in 17 of them.
In a second experiment, the researchers tested how focusing on storytelling affects the “collective” heart rate. Participants watched the short video instructions twice. The first time, with concentration, the second, counting down in their minds (they subtracted 7 from a certain number). In the first case, the authors of the study observed rhythm synchronization. Since the videos did not contain emotional swings, they concluded that the reason for the similar heart rate was not the emotional component of the story. At the same time, the lack of attention on the second scan resulted in decreased synchronization.
In the third experiment, participants listened to children’s stories. Some of them were attentive, others were distracted. The volunteers were then asked to recall some facts from the text. It turned out that the better people could remember a story, the more rhythm sync they had while listening to it. That is, scientists believe that changes in rhythm are associated with the conscious processing of the story.
It is noteworthy that breathing synchronization was not found in the study participants. This was an unexpected find, since the effect of respiration rate on heart rate is well known.
The last experiment included not only healthy volunteers, but also people with impaired consciousness (in a coma, vegetative state, state of minimal consciousness). As expected, the synchronization of the heart rhythm in the second group was weak.
Consciousness returned to one of the two patients with the highest level of heart rhythm synchronization within six months. Scientists do not exclude that its assessment may have predictive value. More research is needed to confirm this.
Lucas Parra of the City College of New York, co-author of the study, summarized that how listeners retain attention is an important factor in heart rate synchronization. It’s not about emotion, he said, but about engagement, mindfulness, and thinking about what’s going to happen next. While listening, the heart, he says, reacts to signals from the brain.
Parra believes that the data obtained are very important for understanding the connection of the brain, specifically – thinking, with the work of the whole organism.