We always knew dogs were empaths.
dog sniffing woman's hand
Credit: Bogdan Kurylo / Getty

It's no secret snuggling up with a dog is a major stress reliever—and a new study suggests our furry friends might be able to sense when we're needing a little extra affection. 

In the study, researchers from the United Kingdom found that not only do humans emit a different odor when experiencing stress, but dogs seem to be able to distinguish it. Four dogs participated in the study, in which they were exposed to a person's "baseline" scent (their scent when in a relaxed state) before smelling the same person's scent after they were stressed. The dogs who took part included a cockapoo, cocker spaniel, and two mixed breeds. 

The dogs yielded some pretty impressive stats when put to the test, enough to make researchers wonder if their findings could make service dogs even more vital.  

To conduct the study, researchers trained the dogs to point out a specific person's scent from a lineup of three different containers holding gauze. One container held the gauze of the target scent the dogs were on the hunt for—while the other containers confined either unused gauze; gauze containing a different person's scent; or gauze containing the same person's scent from a different point in the day. The dogs' goal was to point out the baseline scent of a certain person.  

Once the dogs passed the training, they moved on to the experiment. Prior to bringing the dogs in, the researchers collected sweat and breath samples from 36 participants. They first collected baseline samples, and then collected stress samples after having the participants partake in a mentally strenuous activity: counting backward from 9,000 at intervals of 17. Once the samples were collected, it was time for the dogs to get to work. 

The first test was having the dogs identify the stress sample from three containers, two of which contained unused gauze. Once the dogs got this down, researchers added the baseline sample into the mix. Across all test sessions, researchers found that the four dogs were able to indicate the stress sample 93.75 percent of the time. 

"It was pretty amazing to see them be so confident in telling me, 'Nope, these two things definitely smell different,'" Clara Wilson, lead author of the study, told The Guardian

Wilson also told The Guardian that even though the dogs in the study were trained to detect and acknowledge the scent they were searching for, it's possible untrained dogs may also be able to detect the difference in human odors. 

Researchers believe this study could be beneficial when it comes to how service dogs, such as anxiety and PTSD service dogs, are trained. Instead of being trained to only spot visual cues, which is typically the case, service dogs could also be taught to detect scent clues. 

"They're often trained to look at someone either crouching down on the floor or starting to do self-injurious behaviors," Wilson told the newspaper about service dogs. "There is definitely a smell component, and that might be valuable in the training of these dogs in addition to all of the visual stuff."