Dogs can sniff out stress on owner's breath

Video caption, Four dogs - pets volunteered by their owners - were trained to "choose" one of three scent canisters
  • Author, Victoria Gill
  • Role, Science correspondent

Our canine companions have proven once again how finely tuned they are to our feelings - this time in a scientific sniffing test.

Scientists discovered that dogs can smell stress in our breath and sweat.

Four dogs - pets volunteered by their owners - were trained to "choose" one of three scent canisters.

And in more than 650 out of 700 trials, they successfully identified a sample of sweat or breath that had been taken from a stressed person.

The researchers, at Queen's University Belfast, hope their study, , will help in the training of therapy dogs.

Dogs experience their world through smell. And their highly sensitive scent-detection abilities are already used to detect drugs, explosives, and illnesses, including certain cancers, diabetes and .

"We had lots of evidence that dogs can pick up smells from humans that are associated with certain medical conditions or disease - but we don't have much evidence that they can smell differences in our psychological state," lead researcher Clara Wilson said.

Image source, Victoria Gill

Image caption, A dog's nose is a highly sensitive chemical detector

The 36 human volunteers reported their stress levels before and after completing a difficult maths problem.

Each can contained a sample of their sweat or breath from before or - as long as their blood pressure and heart rate had also increased - after.

And if the dogs, Treo, Fingal, Soot and Winnie, stood still or sat in front of the "stressed" sample, they were rewarded with a favourite dog treat.

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