Are you having a rough day? Whether it’s a change in routine, homework load, tricky math problems, or deadlines, everyday life can be quite stressful.
But what if I tell you dogs or man’s best friend can know when people are stressed?
Yes. You read that right! A dog (if you have a pet at home) can detect when you are stressed out.
A study published in the journal PLOS ONE has found that dogs can smell and detect the difference between odors from humans that are stressed and those that are calm or relaxed.
Now you might wonder, How can dogs detect when people feel stressed?
Our bodies’ response to psychological stress changes the odor of our sweat and breath. And dogs can detect the changes in the scent with a sniff.
Unlike humans, with just 50 million olfactory receptors (the one responsible for detecting odorants), dogs have more than 220 million olfactory receptors. Previous studies have also shown that trained dogs can detect many diseases simply through smell. So it’s no mystery why they are so effective at sniffing out these changes.
The researchers of the latest study collected samples from 36 participants during two scenarios: when they were relaxed and after doing a difficult math problem for three minutes. They also gathered the participants’ blood pressures and heart rates and reported stress levels before and after the assigned task.
Each participant’s sweat samples were collected by wiping a gauze and placing it in a sterile glass vial. Likewise, they were also told to exhale into the vial three times to collect their breath samples.
The team selected four dogs from the Belfast community, Winnie, Treo, Soot, and Fingal, to identify odors from the “stress” and relaxed samples. These four dogs that passed the initial testing phase were trained to differentiate between these odors and were presented with the samples.
The study found that the dogs could accurately sniff out the stressed sample in about 93.8% of the trials. This demonstrates that dogs can indeed determine the change in odor in sweat and breath, which is an acute and negative, psychological stress response.
Although more research is needed to see how the results can be applied in the real world, these findings opened the door to further understanding the “human-dog relationship.” This also helps future studies for training anxiety and PTSD service dogs to respond better to human stress and distress.