Physiological and behavioral reactivity to stress in thunderstorm-phobic dogs and their caregivers

This study addresses interactions between hypothalamic-pituitary-adrenal (HPA) axis activation in response to stress, relationship quality, and behavior in thunderstorm-anxious dogs and their owners. Using a controlled repeated-measures design, we experimentally manipulated exposure of individuals to a stressor they were highly fearful of, and assessed both their own and their caregivers' physiological and behavioral responsiveness. Saliva samples were collected from 19 dog-owner dyads before, 20 and 40 min after exposure to a simulated thunderstorm and were later assayed for cortisol. In response to the challenge, the dogs exhibited classic signs of fear (i.e., pacing, whining, hiding), their cortisol levels increased 207%, and these levels did not return to baseline within 40 min. There were no effects of the owners' behavior or the quality of the dog-owner relationship on the dogs' HPA or behavioral reactivity. However, the presence of other dogs in the household was linked to less pronounced reactivity and more rapid recovery of the dog's HPA response. On average, the cortisol levels of the caregivers did not increase. Owners' mood (e.g. depression, anger) affected their behavioral response towards their dogs. These findings are among the first to study the HPA responsiveness of anxious canines in response to stress in a home setting, and the physiological and behavioral effects of problem canine behavior on their caregivers.