The Effect of Interaction with a Dog on Heart Rate Variability based on Lorenz Plot Analysis

Izuru Nose1, Kaori Masamoto2, Asami Tsuchida3, Mikiya Hayashi4, Mami Irimajiri1,5, and Miki Kakinuma1

1 Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 2 Faculty of Human Sciences, Matsuyama Shinonome College, 3 Faculty of Agriculture, Tokyo University of Agriculture, 4 Faculty of Psychology, Meisei University, 5 Animal Behavior Clinic, Synergy Animal General Hospital

Animal Assisted Intervention (AAI) is widely used in therapeutic and educational situations. It is necessary to describe the effects of AAI based on objective indices to facilitate the effective use of AAI. We investigated the effects of interacting with a dog on sympathetic and parasympathetic nervous system activities by evaluating heart rate variability (HRV) using the Lorenz plot method. Participants were thirty-four healthy volunteers (17 females and 17 males, 20-29 years of age), randomly assigned to one of three groups: the dog group, the stuffed dog group, and the plant group. Participants rated their impressions of the target (the dog, the stuffed dog, or the plant) by touching it between task blocks. The participants completed a mood scale in each block, and we measured their heart rate, respiration rate, and skin conductance response. Results indicated that interactions with the dog increased the cardiac sympathetic index of Lorentz plot, skin conductance responses, and “high-arousal and pleasant mood” score compared to the other conditions. These results suggest that short interactions with a dog activate the sympathetic nervous system, which causes an awakening effect.

Key words: animal-assisted intervention, pet dog, heart rate variability, Lorenz plot

Author Note
This study was supported by JSPS KAKENHI Grant Number 26450457. This study was approved by the ethical committee that serves as the Institutional Review Board of the Nippon Veterinary and Life Science University (26S-49). None of the authors have any known conflicts of interest to disclose.

Correspondence concerning this article should be addressed to Izuru Nose, Laboratory of Comparative Developmental Psychology, Nippon Veterinary and Life Science University, 1-7-1 Kyonancho, Musashino-shi, Tokyo 1808602, JAPAN, E-mail: .

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