Your Dog Can Smell You Stressing Out

Dogs can smell stress from human sweat and breath, meaning their ability to perceive the emotions if the people around them isn’t limited to audio and visual queues, according to a new study out of the United Kingdom. The research findings were published in the journal PLOS ONE. 

Conducted by researchers from Queen’s University Belfast in Northern Ireland, the study focused on four dogs from Belfast — Treo, Fingal, Soot and Winnie — and 36 people.

The research team collected samples of sweat and breath from human participants before and after they worked on a difficult math problem. The human subjects self-reported their stress levels before and after the problem-solving task and researchers only used samples where the person’s blood pressure and heart rate had increased.

The dogs were taught how to search for a specific scent in a line-up and alert researchers to the correct sample. The stress and relaxed samples were then introduced. 

In every test session, each dog was given one person’s relaxed and stressed samples, taken only four minutes apart. Ss it turned out, all the dogs were able to correctly alert the researchers to each person’s stress sample.

Clara Wilson, a doctoral student in the School of Psychology at Queen’s, explains: “The findings show that we, as humans, produce different smells through our sweat and breath when we are stressed and dogs can tell this apart from our smell when relaxed — even if it is someone they do not know.

“The research highlights that dogs do not need visual or audio cues to pick up on human stress.,” she said. “This is the first study of its kind and it provides evidence that dogs can smell stress from breath and sweat alone, which could be useful when training service dogs and therapy dogs.

Wilson further explained the study “also helps to shed more light on the human-dog relationship and adds to our understanding of how dogs may interpret and interact with human psychological states.”

One of the canines sniffers included in the study was Treo, a two-year-old Cocker Spaniel. 

Said Treo’s owner,  Helen Parks: “As the owner of a dog that thrives on sniffing, we were delighted and curious to see Treo take part in the study. We couldn’t wait to hear the results each week when we collected him. He was always so excited to see the researchers at Queen’s and could find his own way to the laboratory.

“The study made us more aware of a dog’s ability to use their nose to ‘see’ the world. We believe this study really developed Treo’s ability to sense a change in emotion at home,” Parks said. “The study reinforced for us that dogs are highly sensitive and intuitive animals and there is immense value in using what they do best — sniffing!”

According to the website PetMD, dogs can smell up to 100,000 times better than humans. In fact, a dog’s sense of smell is its most powerful sense and is actually so sensitive that a canine can detect the equivalent of half a teaspoon of sugar in an Olympic-sized swimming pool. 

One of the things that makes a dog nose superior is that a dog has the ability to breathe in and out at the same time, continues the PetMD explanation.

So, when sniffing, a dog’s nose is designed so that air can move in and out at the same time, creating a continuous circulation of air.