Study Says Petting Dogsbr or Cats Can Reduce Stress A study commissioned by Washington Statebr University has found that comfort from an animalbr can have a “significant impact” on stress levels. In as little as 10 minutes, interacting with animalsbr was found to cause a significant reductionbr of cortisol, the body’s main stress hormone. The study, which involved almost 250 collegebr students, examined four different groups. One group was allowed to interact with the catsbr and dogs for 10 minutes, while the other threebr groups either observed or remained isolated. Researchers then took saliva samples from thebr participants and found that those who directlybr interacted with the animals had less cortisol. Patricia Pendry, an associatebr professor at WSU, believes thebr study shows “exciting” results.