Effect of dog-walking on autonomic nervous activity in senior citizens

OBJECTIVE: To compare changes in autonomic nervous activity in healthy senior individuals while walking with and without a dog, and during routine activities at home and periods of interacting with the dog at home. DESIGN: Controlled crossover study. PARTICIPANTS AND SETTING: 13 healthy volunteers (3 men, 10 women; mean age, 67.5 years) who walked in a park adjacent to Gunma University, Japan, and 4 volunteers among these who underwent monitoring in their own homes. INTERVENTIONS: Heart rate variability was monitored continuously by means of a palm-sized electrocardiographic monitor (which facilitated spectral analysis of the RR interval) while participants walked for 30 minutes (first with, then without, the study dog, or vice versa); three participants underwent this intervention on 3 consecutive days. Four participants underwent continuous monitoring for 6 hours in their own homes, including two 30-minute periods of free interaction with the study dog. MAIN OUTCOME MEASURES: High frequency (HF) power values of heart rate variability, which is a measure of parasympathetic neural activity. RESULTS: During dog-walking, HF power increased significantly (P < 0.01); this increase was sustained throughout each dog walk, and was more pronounced during succeeding dog walks. At home, HF power was 1.87 times greater when the dog was present, and 1.57 times greater (P < 0.01) than in the walking experiment. CONCLUSIONS: Walking a dog has potentially greater health benefits as a buffer against stress in senior citizens than walking without a dog; and, independent of actually walking, merely patting and talking to a dog also raises parasympathetic neural activity. Power spectral analysis of heart rate variability shows promise as a non-invasive approach to quantifying clinicophysiological research on human health benefits possibly derived from interaction with companion animals.