Dogs can sniff out the stress in humans, study suggests

Dogs were also able to identify when humans were relaxed, reports Furvah Shah

The study ‘helps to shed more light on the human-dog relationship’, say researchers (Getty Images/iStockphoto)

Dogs can sniff out stress in humans, according to a new study.

Researchers at Queen’s University Belfast found that dogs were able to detect when humans were stressed or relaxed through smell.

Clara Wilson, a PhD student at the university’s School of Psychology, said the study provides “evidence that dogs can smell stress from breath and sweat alone, which could be useful when training service dogs and therapy dogs”.

For their work, researchers collected samples of sweat and breath from 36 people before and after they tried to complete a difficult maths problem.

Each participant reported their stress levels before and after the task, and researchers presented the dogs with samples where the person’s blood pressure and heart rate had increased.

When presented with the samples, all four dogs – Treo, Fingal, Soot and Winnie – were able to correctly identify the stress specimens.

Ms Wilson added: “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.

The study’s findings could be “useful when training service dogs and therapy dogs,” say researchers (Getty Images/iStockphoto)

“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.

“It 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 dogs that took part in the study was Treo, a two-year-old cocker spaniel.

His owner, Helen Parks, said: “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.

“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.”

The study’s findings are published in the Plos One journal.