Dogs Can Smell Stress In Humans

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Research has shown that dogs can help reduce negative feelings like stress and loneliness. Now, a new study suggests that dogs can not only reduce stress — they can also smell it. Researchers from Queen's University Belfast and Newcastle University wanted to find out if dogs could tell the difference between a person's regular smell and how they smell when they're stressed. To do this, they first collected sweat and breath samples from participants to use as a baseline. To make sure the samples were not affected by anything else, the participants were all non-smokers and didn't eat or drink anything in the hour before the study. 

The participants were asked to report their stress levels before and after the task. The researchers also checked participants' stress levels before and after the task by taking their heart rates and blood pressure. In total, 36 out of 53 participants reported feeling stressed because of the task and had increased heart rates and blood pressure. Both their baseline and stress samples were then shown to four dogs, who were asked to find the participant's stress sample.

The results, published in PLOS One, showed that the dogs had nearly 94% accuracy in detecting the stress samples.

According to Clara Wilson, one of the researchers, the study shows that dogs don't need to look at or listen to a person to detect stress — breath and sweat smells are enough. She added that the study could also help us understand more about the relationship between dogs and humans, and how much dogs know about what humans are feeling.