New research investigates the physiological changes associated with human-animal interactions.

In recent years, scientific evidence supporting the health and wellbeing benefits of human-animal interaction (HAI) has grown rapidly, especially for dogs. Previous research has revealed that dog ownership can have a positive impact on blood pressure, physical function, social connectivity and stress. Research has even found that dog owners are more likely to survive after cardiac arrest than non-pet owners.

However, far fewer studies have investigated the psychophysiological mechanisms that underpin these effects, limiting our understanding. For this reason, researchers from the University of Wollongong, Australia, recently published a study which investigated changes in owners’ heart and brain function when they interacted with their dogs.

New study into HAI mechanism

The study recruited 50 dog owners without serious physical or psychological health conditions. Participants completed a demographic and screening questionnaire, after which a further four participants were excluded due to mental health conditions. The experimental procedures took place at the participants’ homes to replicate a more naturalistic setting for dog-owner interactions.

The measures captured included subjective units of relaxation, as well as continuous electroencephalogram (EEG), heart rate (HR) and heart rate variability (HRV) via portable devices. All participants experienced five experimental conditions which allowed researchers to isolate the effect of different aspects: resting (baseline), relaxation exercise, toy dog petting, real dog presence (no touch), real dog petting.

Brain and heart benefits

The findings revealed that participants reported significantly higher subjective units of relaxation when petting the real dog compared to the baseline, suggesting that petting a real dog induces more relaxation than resting. However, petting the real dog was not significantly higher than during the relaxation exercise or petting a toy dog, suggesting that they could be used as an alternative in situations where real dogs are not feasible.

The EEG data revealed that petting the real dog produces significant changes in brain activity, including increased power in delta, theta, alpha, and beta brainwave frequencies. Delta and theta brain waves are known to be linked to deep relaxation, like in meditation. Alpha waves on the other hand indicate an alert state, and beta waves are connected to active thinking. This combination suggests that whilst interacting with a dog is relaxing, it also promotes engagement and focus.

Interacting with a real dog was also associated with a significant increase in HR compared to other conditions. This is likely due to the physical activity needed to interact with the dog and also physical arousal produced by it. HRV was also significantly higher in the real dog petting condition, suggesting that interacting with a real dog promotes parasympathetic activity. Interestingly, the same effect was also present in the real dog presence condition, suggesting that dogs can improve parasympathetic activity without contact.

Study implications

The findings of this study improve our understanding of the health benefits of human-dog interactions by providing insights into the underlying psychophysiological mechanisms that underpin them. Whilst previous studies have showed that dog ownership is associated with reduced stress, lower blood pressure and better cardiovascular health, very few studies have investigated specific changes in brain activity and heart rate variability that occur when interacting with dogs.

Overall, the study adds to the growing body of evidence supporting the health benefits of pet ownership, offering new insights into the psychophysiological mechanisms that underlie these benefits. By showing that interactions with dogs can lead to significant changes in brain activity, HR, and HRV, the findings highlight the unique role that dogs can play in promoting relaxation, focus, and cardiovascular health.

Key study findings

• Petting a real dog was not significantly more relaxing than a relaxation exercise or petting a toy dog
• Petting a real dog increased power in delta, theta, alpha, and beta brainwave frequencies
• Petting a real dog increased HR and HRV