Pet Ownership and Physical Health

Robert L. Matchock


Curr Opin Psychiatry. 2015;28(5):386-392. 

In This Article

Mechanisms of the Pet Effect

The underlying mechanisms that mediate the beneficial effects of companion animals are poorly understand, but it is likely that there are multiple mechanisms involved that are not mutually exclusive and that act in tandem. Decreases in cardiovascular parameters such as HR and BP[51,52] are likely to be potent contributors to the pet–health link, as suggested by several reviews,[57] including a statement by the American Heart Association.[26] Improvements in cardiovascular functioning likely stem from direct contact and attachment with a pet, as well as increases in physical activity as would be the case for dog walking.

Odendaal and Meintjes[58] had 18 human adults affiliatively interact with 18 different dogs. After the interaction, mean arterial BP and cortisol decreased, while β-endorphin, oxytocin, prolactin, phenyl acetic acid, and dopamine increased. These same beneficial hormonal increases and decreases were also observed with the dogs (with the exception of cortisol). Attenuation of cortisol via exposure to an unfamiliar but friendly dog has been documented in other studies as well.[53,54] Among owners attached to their dogs, the longer dogs gazed at their owners, the higher the level of oxytocin in the owners, at least as measured by urinary oxytocin,[59] which may not be the most reliable way to sample oxytocin.[60] Furthermore, if dogs are given intranasal oxytocin, dogs affiliate more with, and have more social orientation toward, their human owners.[61] Beetz et al.[6] cogently argue that most beneficial psychological and physiological effects of HAIs are mediated by the pituitary peptide hormone, oxytocin (e.g., attenuating both components of the hypothalamic-pituitary-adrenal axis – glucocorticoids and cardiovascular responsiveness). Oxytocin is traditionally viewed as being implicated in parturition and lactation, but its importance in social bonding is starting to be recognized.[6] More research is needed on the biochemical correlates of HAIs, especially cortisol and oxytocin.

Possible psychological mechanisms of the pet effect are likely to be inexorably linked to some of the above physical parameters but include pets inducing a greater sense of responsibility,[28] serving as a social catalyst[62] (e.g., pets elicit more conversations, smiles, and other social interactions from people), and loneliness alleviation.[19,25]