HARLINGEN, Texas (ValleyCentral) — A recent study shows that dogs may be able to smell when humans are stressed.

The study, titled “Dogs can discriminate between human baseline and psychological stress condition odours” was published in, PLOS One, a science-medicine journal.

The study tested whether “baseline” and “stress [odors]” were distinguishable to dogs. The testing used a double-blind, two-phase procedure where breath and sweat samples were taken from participants.

The dog was presented with a participant’s stress sample alongside two blanks and was required to identify the stress sample with an “alert behavior.”

In the second phase, the dog was presented with the stress sample, a baseline sample and a blank and was asked for another alert.

According to the study, the dogs displayed a combined accuracy of 93.75 percent.

“Our findings demonstrate that there is a detectable [odor] associated with acute negative stress that is distinct from [odors] at baseline,” the study stated. ” While the dogs in this study underwent training in order to communicate that they were able to distinguish between [odors], the found performances on this task suggests that there are VOC (volatile organic compounds) changes induced by acute negative stress that are detectable by dogs.”

Along with the suggested changes in VOC, human stress is associated with the release of epinephrine and cortisol into the bloodstream, the study stated.

According to a post by the Phoenix Veterinary Center, dogs have up to 300 million olfactory receptors in their noses, whereas humans have about six million. The portion of the dog’s brains responsible for analyzing scents is also “40 times greater than ours,” the post stated.