Scientists Study Horse, Human Heart Coupling

Have you ever felt that special connection with your horse? Have you had that feeling that you and your horse are on the same wavelength, connected as one, following the same emotions, and bonding through some invisible link?

Italian researchers are hot on the trail to understand what exactly is going on with that connection so many riders and owners claim to feel. Through high-tech research using wearable monitoring systems and advanced algorithms, they’ve determined that horses and humans tend to align their physiological responses to emotional stimulation.

At least, that’s the case in this preliminary study, said Paolo Baragli, DVM, PhD, researcher in the University of Pisa Department of Veterinary Sciences, in Italy. Along with colleague Antonio Lanata, PhD, of the University of Pisa’s E. Piaggio Bioengineering and Robotics Research Center and the Department of Information Engineering, he’s investigating the mysteries of the horse-human heart connections.

In their pilot study, they tested cardiac parameters of 11 humans and one mare as the humans individually spent time with the horse. They divided the test into three parts:

• In Part 1, the human sat still in a chair in a stall next to the horse.
• In Part 2, the human continued to sit still in the chair, but the horse entered the stall with the human and could explore the human through sniffing and touching.
• In Part 3, the human groomed the horse.

The researchers recorded the horse’s and human’s heart rate and heart rate variability (HRV, the slight changes in heart rate from beat to beat) during each interaction. They then analyzed the data using specialized signal processing algorithms.

They found that horses and humans tended to “couple” their HRV—a strong indicator of emotional status—in Part 2 compared to Part 1, during which they were separated, Baragli said. However, in Part 3, the coupling began to dissolve, with more differentiation in HRV between horse and human.

“In Part 2 the horse is free to move and can decide by himself to approach the human or not,” Baragli said. “In Part 3 the horse is ‘forced’ to the contact with human. The opportunity to have choice is one of the new frontiers of animal well-being and, in that way, our very preliminary results seem to confirm that giving the animals the opportunity to have a choice meets their emotional requirements.

“This preliminary study is as an attempt to approach research on interspecific emotional transfer, which could be relevant in the assisted intervention with horses but even in the day-to-day relationship for leisure and sport,” he added. “Essentially, it seems that the quality and timing of the contact itself affect the emotional arousal between two different species.”

In this early stage of research, it’s not possible to confirm the trend, however, Baragli said. If future studies confirm it, “that would mean that both autonomic nervous systems of horse and human can be influenced reciprocally,” he said. “This could be a sign of an emotional transfer between horse and human. But at this point we cannot exclude other and less relevant reasons, like chance.”

Future research will require funding that’s not yet available, he added. “The experimental design is ready,” he said. “We’re just missing the grants.”

The study, “Quantitative heartbeat coupling measures in human-horse interaction,” was published in the Proceedings of the IEEE 38th Annual International Conference of the Engineering in Medicine and Biology Society.