The impact on pain reduction may be explained by the current
understanding of the role of pets in modulating a psychoneuroendocrine response.51,52 In this response, emotions promote biochemically-mediated neurologic and immune responses to
emotionally-based stimuli. In other words, exposure to a pet or
other friendly animal induces the release of endorphins, which
induce a feeling of well-being, and lymphocytes, which increase the
immune response. Physiologic indicators, such as reduced heart
rate, reduced blood pressure, reduced respiratory rate, increased
peripheral skin temperature, and papillary constriction are indicative of decreased sympathetic nervous system activity and the
activation of the parasympathetic nervous system indicative of the
relaxation response.39 Interestingly, the children in the AAT group
demonstrated a slight increase in respiratory rate (2 breaths/min),