Stress has an odor and dogs can smell it …

Dogs can smell stress from human sweat and breath, a new study by Queen’s University Belfast researchers has found.

The study involved four dogs from Belfast – Treo, Fingal, Soot and Winnie – and 36 people.

Researchers collected samples of sweat and breath from participants before and after they did a difficult maths problem. They self-reported their stress levels before and after the task and researchers only used samples where the person’s blood pressure and heart rate had increased.

The dogs were taught how to search a scent line-up and alert researchers to the correct sample. The stress and relaxed samples were then introduced but at this stage the researchers didn’t know if there was an odour difference that dogs could detect.