New research examines how interacting with pets affects cortisol levels among college students.

Pet owners have long known—or rather, felt—that spending time with their beloved animal companion lowers stress and improves mood. An extensive review that Medical News Today reported on included several testimonials from people living with mental health conditions who vouched for the emotional comfort and psychological benefits that their pets brought them.

In fact, the review concluded that pets should be part of patient care plans because of their valuable contribution to people's mental health and well-being. Now, new research adds more scientific credibility to these claims. Researchers Patricia Pendry, an associate professor in the Department of Human Development at Washington State University in Pullman, and Jaymie L. Vandagriff, of the same department, set out to examine the effect of pets on the physiology of college students. The researchers published their findings in the journal AERA Open, of the American Educational Research Association.

Pets lower cortisol levels

The scientists recruited 249 college students and divided them into four groups:

• In one group, people were free to spend time with cats and dogs for 10 minutes, stroking and playing with the animals
• Another group observed other people interacting with the animals while they were waiting for their turn
• Another group watched a slideshow of the animals
• The final group simply sat and waited in silence

Pendry and Vandagriff also collected samples of the participants' saliva and tested their cortisol levels both in the morning and after the intervention. Cortisol is a hormone that the body secretes in response to stress.

To examine the effects of the intervention on cortisol levels, the researchers applied multivariate linear regression analyses. Overall, the analysis revealed that the students who interacted with the animals had significantly lower cortisol levels after the intervention. These effects occurred regardless of whether the participants' initial cortisol levels were very high or very low at the start of the study.

"Students in our study that interacted with cats and dogs had a significant reduction in cortisol, a major stress hormone," reports study co-author Pendry.

She adds, "We already knew that students enjoy interacting with animals, and that it helps them experience more positive emotions. What we wanted to learn was whether this exposure would help students reduce their stress in a less subjective way. And it did, which is exciting because the reduction of stress hormones may, over time, have significant benefits for physical and mental health."

"Just 10 minutes can have a significant impact," adds Pendry, but she and her colleagues now plan to examine the effect of a similar 4-week program, in which animals would hopefully help relieve stress. The preliminary results are promising.

This was the first study to involve college students and show reductions in levels of the stress hormone cortisol in a real-life setting rather than a laboratory.