The bond between dogs and their owners is often described as one of deep loyalty and companionship, but a new study from the University of Jyväskylä reveals there’s more to this relationship than meets the eye—or the heart. Researchers have found that a dog’s heart rate variability (HRV) adapts to its owner’s HRV, suggesting a physical synchrony in emotional states. This groundbreaking research sheds new light on how dogs and owners influence each other’s wellbeing through an emotional and physiological connection.

Heart rate variability, or the variation in intervals between heartbeats, reflects the state of the autonomic nervous system. High HRV is associated with relaxation, while low HRV often indicates stress. In this study, owners and dogs were monitored during various tasks and found to share synchronized HRV levels during resting periods. When the owner was relaxed, their dog reflected that calmness with higher HRV, and similarly, during physical tasks, both the activity levels and HRV patterns between the two mirrored each other.

Dr. Aija Koskela, a doctoral researcher involved in the study, noted that the clearest connection between owner and dog HRV was observed during relaxed, free-form resting. Without any active tasks, owners and dogs seemed to respond naturally to each other’s states, underscoring an emotional synchrony that deepens their bond.

Interestingly, the study also revealed that an owner's temperament influenced their dog's HRV. Dogs of owners with higher “negative affectivity”—a tendency to experience concern and sensitivity to negative events—exhibited higher HRV levels, likely feeling a heightened sense of security with these attentive owners. In another surprising discovery, the dog’s HRV turned out to be a strong predictor of the owner’s HRV, indicating that the dog’s emotional state has a tangible impact on its human’s wellbeing.

Led by Academy Research Fellow Miiamaaria Kujala, this study took a novel approach by simultaneously monitoring the heart rates and activity levels of both dogs and owners, making it one of the few studies to explore this bidirectional relationship. “The challenging research setting offers a unique perspective on the interactive aspects of this bond,” Kujala noted.

Funded by the Research Council of Finland and the Agria & Svenska Kennelklubben Research Fund, the study involved 30 owners and their dogs, primarily sheep dogs and retrievers—breeds selected for their cooperative nature. The findings, published on October 24, 2024, in Scientific Reports, provide a compelling look at how emotionally connected dog-owner relationships are strengthened by physiological adaptations similar to those that enhance bonding between human family members.

With these insights, the researchers aim to delve deeper into the biological mechanisms behind this heart-brain connection, furthering our understanding of how companionship with dogs enhances human lives and contributes to mental health.