Dogs can smell the stress odor in humans: Research

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.

In every test session, each dog was given one person's relaxed and stressed samples, taken only four minutes apart. All of the dogs were able to correctly alert the researchers to each person's stress sample.

The research highlights that dogs do not need visual or audio cues to pick up on human stress. 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.

Reference:

Clara Wilson et al,PLoS ONE