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.
- 1. Akiyama H, Holtzman JM, Britz WE. Pet ownership and health status during bereavement. Omega J Death Dying 1987; 17: 187-193.
- 2. Garrity TF, Stallones L, Marx MB, Johnson TP. Pet ownership and attachment as supportive factors in the health of the elderly. Anthrozoos 1989; 3: 35-44.
- 3. Siegel JM. Stressful life events and use of physician services among the elderly: the moderating role of pet ownership. J Pers Soc Psychol 1990; 58: 1081-1086.
- 4. Mugford RS, M’Cornisky JG. Therapeutic value of cage birds with old people. In: Anderson ER, editor. Pet animals and society. London: Balliere Tindall; 1975: 54-65.
- 5. Serpell JA. Beneficial effects of pet ownership on some aspects of human health. J Roy Soc Med 1991; 84: 717-720.
- 6. Friedmann E, Katcher AH, Lynch JJ, Thomas SA. Animal companions and one year survival of patients after discharge from a coronary care unit. Public Health Rep 1980; 95: 307-312.
- 7. Baun MM, Bergstrom N, Langston N, Thoma L. Physiological effects of human/companion animal bonding. Nurs Res 1984; 33: 126-129.
- 8. Katcher AH. Interactions between people and their pets: form and function. In: Fogle B, editor. Interrelationships between people and pets. Springfield, Ill: Charles C Thomas; 1981: 41-67.
- 9. Anderson W, Reid P, Jennings GL. Pet ownership and risk factors for cardiovascular disease. Med J Aust 1992; 157: 298-301.
- 10. Malliani A, Pagani M, Lombardi F, Cerutti S. Cardiovascular neural regulation explored in the frequency domain. Circulation 1991; 84: 482-492.
- 11. Pagani M, Lombardi F, Guzzetti S, et al. Power spectral analysis of heart rate and arterial variabilities as a marker of sympatho-vagal interaction in man and conscious dog. Circ Res 1986; 59: 178-193.
- 12. Akita M, Ishii K, Kuwahara M, Tsubone H. Power spectral analysis of heart rate variability for assessment of diurnal variation of autonomic nervous activity in guinea pigs. Exp Anim 2002; 51: 1-7.
- 13. Hagiwara Y, Tsubone H, Kuwahara M. Effects of endotoxin on cardiovascular and autonomic nervous system in rats. Jpn J Electrocardiol 2001; 21: 164-173.
- 14. Hashimoto M, Kuwahara, M, Tsubone H, Sugano S. Diurnal variation of autonomic nervous activity in the rat: investigation by power spectral analysis of heart rate variability. J Electrocardiol 1999; 32: 167-171.
- 15. Kuwahara M, Suzuki A, Tsutsumi H, et al. Power spectral analysis of heart rate variability for assessment of diurnal variation of autonomic nervous activity in miniature swine. Lab Anim Sci 1999; 49: 202-208.
- 16. Grassi G, Esler M. How to assess sympathetic activity in humans. J Hypertension 1999; 17: 719-734.
- 17. Kingwell BA, Thompson JM, Kaye DM, et al. Heart rate spectral analysis, cardiac norepinephrine spillover, and muscle sympathetic nerve activity during human sympathetic nervous activation and failure. Circulation 1994; 90: 234-240.
- 18. Kuwahara M, Yayou K, Ishii K, et al. Power spectral analysis of heart rate variability as a new method for assessing autonomic activity in the rat. J Electrocardiol 1994; 27: 333-337.
- 19. Kuwahara M, Hashimoto S, Tsubone H, Sugano S. Developmental changes of autonomic nervous activity in spontaneously hypertensive rats: investigation by power spectral analysis of heart rate variability. J Ambul Monit 1996; 9: 51-58.
- 20. Friedmann E, Thomas SA. Pet ownership, social support, and one-year survival after acute myocardial infarction in the cardiac arrhythmia suppression trial (CAST). Am J Cardiol 1995; 76: 1213-1217.
- 21. Friedmann E, Katcher A, Thomas SA, et al. Social interaction and blood pressure: influence of animal companions. J Nerv Ment Dis 1983; 171: 461-465.
- 22. Oben JA, Roskams T, Yang S, et al. Sympathetic nervous system inhibition increases hepatic progenitors and reduces liver injury. Hepatology 2003; 38: 664-673.
Publication of your online response is subject to the Medical Journal of Australia's editorial discretion. You will be notified by email within five working days should your response be accepted.